The Mature Driver: Safety and Mobility Issues

SUMMARY

This project surveyed both the literature and the practice to examine the variables that relate to aging drivers and safety. In addition, analysis was done of accident and violation data in New Jersey from 1993-2000.

Demographic Trends In New Jersey

New Jersey’s older population (age 65 and older) is growing at a somewhat faster rate than that of the United States as a whole and this trend of accelerated aging is expected to continue for at least the next 10 years. Two counties in particular, Cape May and Ocean, have a noticeably larger percentage of older residents (both over 20%) than the other counties of the state which hover in the 9-15% range.

The percentage of older citizens of New Jersey who were licensed drivers in 2000 was highest for the 55-64 age group and then dropped slowly for the 65-74 and the 75-84 cohorts. At 85, a marked drop was noted. If older cohorts show an increase in the percentage of licensed drivers, as is the national trend, then we can expect more senior drivers on the roads. If the current numbers do not move much, it suggests that older drivers in New Jersey may be self-screening themselves in terms of driving capability or they may have their licenses suspended or revoked due to medical review. These data need to be tracked to give some indication of the trends in New Jersey.

Analysis of Accident and Violation Data

The results of the analyses of accident and violation data reveal that New Jersey’s older drivers show a propensity to accidents and a pattern of accidents that are similar to outcomes reviewed in Chapter 3

Our data show that number of crashes that the mature driver is involved with decline with age. Further, the rate of crash involvements per population also declines with age. The rate of crash involvements per licensed drivers declines with age until the mid-nineties.

Like older drivers in other states, New Jersey older drivers are involved in more accidents during daylight hours and good weather, probably because they avoid driving in the dark and bad weather. They have more accidents on local and private roads than younger drivers, again probably due to their choice to avoid driving on high-speed roads.

A greater percent of the crashes that a mature driver is involved in are fatal, but they are involved in fewer fatal accidents than younger drivers.

A greater percent of the accidents that a mature driver is involved in were while making a left turn than is true for younger drivers. The crashes that the mature driver is in are more likely to involve inattention, failure to yield right of way, or failure to obey traffic signals. The mature driver is more likely to be at fault than a middle age driver.

The mature driver has a lower rate of traffic violations per population than younger drivers, and the mature driver’s violation is more frequently due to careless driving and less frequently due to speeding. The mature driver has a lower rate of suspensions than the middle aged driver, and the likelihood of the suspension being due to physical or medical conditions increases rapidly as the driver ages, reaching 100 percent for drivers over 90 year old.

In summary, the average mature driver has different types of accidents in different places and times than the younger driver. Many mature drivers appear to be less safe drivers than middle-aged drivers in many ways, but mature drivers as a group are involved in fewer accidents and fewer fatal accidents than younger drivers.

Survey of State Motor Vehicle Associations

The survey of State Motor Vehicle Associations, a combination of email and phone interview, yielded responses from 23 states. The survey was designed to elicit information about age related provisions in licensing and studies in the state regarding older drivers. Of the 23 states responding to the survey, six reported some type of age-related provision in the licensing law. The simplest provision was solely reducing the renewal cycle period. Other renewal provisions included no mail renewal after a certain age, eligibility to be selected for a sample of drivers requiring medical examination, and the need to be re-tested on knowledge and road skills.

Most interestingly, states frequently reported use of medical review as a basis for restricting or suspending the license of elderly drivers. Health care providers, law enforcement officers, agents of the licensing agency, and concerned relatives and friends, can typically initiate medical review. The request for medical review is examined by the licensing agency and a determination is made regarding the need for further information. Very few states had mandatory reporting of medical conditions, with Pennsylvania being the most stringent. Where a determination is made to do something about the driving privilege, several states reported use of restricted licenses rather than suspension or revocation. Typical restrictions include daylight driving, restricted driving range, speed, and type of highway. Some states are providing or recommending remediation courses to improve driving skills.

Several states have concluded, are currently conducting, or are planning to conduct studies regarding older drivers. The thrust of research seems to focus on developing tests that will effectively assess functional ability to drive, including cognitive and physical abilities. Maryland, California, and Florida are the lead states in this effort. Along with test development is concern that there be appropriate remediation facilities that can assist older drivers in improving their driving abilities.

Conclusions

Analyses of the data support other studies that show older drivers do not present an increased crash risk to other drivers. Older drivers appear to be primarily a risk to themselves in that there is a slight increase in fatalities as they get past the age of 65. This is attributed to increased frailty of older drivers.

The pattern of accidents of older drivers in New Jersey suggests that older drivers are already avoiding hazardous driving conditions. Similar to national trends, they have more accidents during the daytime; are less likely than younger drivers to be in accidents when weather and road conditions are poor; and are somewhat more likely to have accidents on local roads than state or interstate highways.

Older drivers in New Jersey, like elsewhere, show a greater propensity to be involved in left-turn accidents than younger groups. This fact combined with the data showing that inattention is the most frequently cited contributing circumstance for older drivers suggests three remedies: training older drivers for intersection maneuvers, redesigning high accident rate intersections, and employing a device that could warn drivers of on-coming cars and whether they can get through the intersections safely.

The analyses of violations data reveal that careless driving is the most frequent citation. Speeding is not an issue. Careless driving is difficult to remedy. A proposed solution is one of training and giving older drivers techniques for focusing their attention while behind the wheel.

Our survey of practices in other state licensing agencies suggest that medical review is used as a way of ending the driving privilege for older drivers who show impaired driving skills. Several states offer restricted licenses. New Jersey might explore the experiences of other states that offer restrictions on driving licenses. Based on those experiences, a policy change might be warranted

An area for further study that emerged from our analyses is the medical review policy in each of the states. There is variability as to how it is initiated, whether there is mandatory physician reporting, whether there is confidentiality of reporting, how the medical review process works, and finally if there are alternatives to suspending or restricting licenses. Examination of the medical review policy in all states would provide a knowledge base for good practice.

Based on the results of the literature review, data analysis and survey of practices in other states, several recommendations are offered.

INTRODUCTION

New Jersey is gaining an aging population like the rest of the United States but more so. In 1990, people 65 and older comprised 12.5 percent of the population in United States while in New Jersey this group represented 13.2 percent. By 1998, this group had increased to 12.7 percent in the U.S. and 13.6 percent in New Jersey. Not only is this age category witnessing increase, within it the oldest old (people 85 and older) is also increasing. With the increase in older population comes an increase in the number of older drivers. From National Highway Traffic Safety Administration’s (NHTSA) data archives, there were 18.5 million older licensed drivers in 1999.⁽¹⁾ This represents an increase of 39 percent from 1989 which contrasts to a 13 percent growth in total licensed drivers during this ten-year period. The rapidly expanding segment of the older driver continues growth that Waller⁽²⁾ noted ten years ago.

A problem clearly emerges for concerns regarding public policy and the quality of life for older drivers when these demographic data are coupled with well established data documenting the association of increased age with risk of injury or death in an automobile crash (e.g., Pike⁽³⁾) and the higher accident rate (per million miles driven) of the older driver.⁽⁴⁾

Given the potential problem of increased accidents occurring on the

densely traveled roads of New Jersey, the New Jersey Department of Transportation in conjunction with the National Center for Transportation and Industrial Productivity requested a study to capture the dimensions of the issues regarding older drivers in the state. New Jersey’s demographics coupled with the fact that it is the most densely populated state with congested roadways necessitates looking at both accident and violation data to understand the extent and nature of the problems regarding senior drivers.

The project’s objective was to survey both the literature and the practice to build a knowledge base of the variables that relate to aging drivers and safety. Included in this knowledge base are the current activities and policies pertaining to older drivers in selected Departments of Motor Vehicles (DMVs) of other states. In addition, the study would provide an understanding of the problems of older drivers in New Jersey by examining existing accident and violation data

The anticipated result of this project is to assist the Department of Transportation and the Division of Motor Vehicles in its efforts to respond to safety and policy issues regarding older drivers. This final report summarizes findings from the literature review, presents the methodology used in its survey of Departments of Motor Vehicles as well as the results of the survey and the results of accident and violation data analysis.

THE MATURE POPULATION OF NEW JERSEY

Older Population of New Jersey

New Jersey, like the United States as a whole, has an aging population. By the year 2000, the number of New Jersey residents who were 65 or older was over 1.1 million or 13.2 percent of the total population, higher than the 12.4 percent for the United States as a whole, while the old old or the 85 and older group had reached 136,000 or 1.6 percent, slightly greater than the 1.5 per cent of the United States population in that age group.⁽⁵⁾ See Table 1.

Table 1. Population 55 Years and Over (Year 2000)

	Total		55 - 64		65 years +		85 +
	no.	percent	no.	percent	no.	percent	no.	percent
United States	281,421,906	100	24,274,684	8.6	34,991,753	12.4	4,239,587	1.5

New Jersey	8,414,350	100	753,984	9.0	1,113,136	13.2	135,999	1.6

Table 2 indicates that for the United States, the 65 plus and the 85 plus groups have been growing at about the same rate of 37 percent. In New Jersey, growth of the 65 and older group has increased at not quite 30 percent; when the fact that New Jersey is a slow growth state (only a 14 percent increase since 1980, compared to 24 percent for the whole country), this is a major increase. New Jersey’s 85 and older category has increased over 94 percent in the 20 year period, a remarkable increase. Referring to Table 1 above indicates that the 55 to 64 age group is proportionally greater in New Jersey than the United States as a whole, suggesting that the trend for New Jersey to age faster than the country as a whole will continue.

Table 2. Growth of Population 1980 to 2000

	Growth in		Growth in		Growth in
	total population		65+ population		85+ population
	Number	percent	Number	percent	Number	percent
United States	54,876,101	24.2%	9,493,367	37.2%	1,159,422	37.6%

New Jersey	1,049,527	14.3%	256,028	29.9%	66,002	94.3%

The counties with the largest 65 and older population are Bergen, Ocean, Essex, and Middlesex (Table 3). However, if we look at the proportion of the county’s population that is older, the larger counties (Bergen, Middlesex, and Essex) are less prominent and Ocean and Cape May are the dominant counties. For the 85 and older category, the same pattern is seen.

Table 3. Population of New Jersey Counties (2000)

	Total	65 years +		85 +
County	population	no.	percent	no.	percent
Atlantic	252,552	34,437	13.6	4,118	1.6
Bergen	884,118	134,820	15.2	17,055	1.9
Burlington	423,394	53,218	12.6	5,491	1.3
Camden	508,932	63,769	12.5	7,543	1.5
Cape May	102,326	20,681	20.2	2,625	2.6
Cumberland	146,438	19,087	13.0	2,316	1.6
Essex	793,633	94,380	11.9	12,311	1.6
Gloucester	254,673	29,678	11.7	3,062	1.2
Hudson	608,975	69,271	11.4	8,245	1.4
Hunterdon	121,989	12,228	10.0	1,399	1.1
Mercer	350,761	44,140	12.6	5,426	1.5
Middlesex	750,162	92,590	12.3	9,424	1.3
Monmouth	615,301	76,923	12.5	9,814	1.6
Morris	470,212	54,530	11.6	6,652	1.4
Ocean	510,916	113,260	22.2	14,914	2.9
Passaic	489,049	59,033	12.1	7,697	1.6
Salem	64,285	9,311	14.5	1,092	1.7
Somerset	297,490	33,381	11.2	4,129	1.4
Sussex	144,166	13,152	9.1	1,626	1.1
Union	522,541	72,041	13.8	9,369	1.8
Warren	102,437	13,206	12.9	1,691	1.7

The rate of growth of the older age categories (Table 4) differ widely between the counties, ranging from a negative 4.3 percent over 20 years for Essex (the overall population of Essex has been shrinking) to 86.5 percent for Burlington County. The counties with the largest absolute increase in the 65 and over population are Ocean, Middlesex, Bergen, and Burlington. The counties with the highest rate of growth tend to be those with smaller population (Burlington, Somerset, and Gloucester) with one exception, Middlesex. For the 85 years and older population, the fastest growing counties are Ocean, Middlesex, Burlington, and Cape May.

Licensed Drivers

Table 5 shows the number and percent of the New Jersey population who have drivers licenses in the older age categories.⁽⁶⁾ While close to 95 percent of the population in the 55 to 64 age category has a drivers license, this drops off as the age increases, reaching less than 50 percent for the 85 plus age category. Actual driving (and therefore exposure to accidents) probably drops off even steeper, as many people keep their license even after ceasing to drive plus the amount that the older person drives is less than people in the prime years of life.

Table 4. Population Growth in New Jersey Counties

1980 to 2000

	Growth in		Growth in		Growth in
	total population		65+ population		85+ population
	Number	percent	Number	percent	Number	percent
New Jersey	1,049,527	14.3%	256,028	29.9%	66,002	94.3%

Counties
Atlantic	58,433	30.1%	3,733	12.2%	1,261	44.1%
Bergen	38,733	4.6%	29,954	28.6%	8,017	88.7%
Burlington	60,852	16.8%	24,679	86.5%	3,096	129.3%
Camden	37,282	7.9%	14,845	30.3%	3,931	108.8%
Cape May	20,060	24.4%	3,987	23.9%	1,436	120.8%
Cumberland	13,572	10.2%	3,567	23.0%	1,131	95.4%
Essex	-57,483	-6.8%	-4,260	-4.3%	4,057	49.2%
Gloucester	54,756	27.4%	11,990	67.8%	1,529	99.7%
Hudson	52,003	9.3%	-409	-0.6%	3,067	59.2%
Hunterdon	34,628	39.6%	4,123	50.9%	651	87.0%
Mercer	42,898	13.9%	9,008	25.6%	2,563	89.5%
Middlesex	154,269	25.9%	40,017	76.1%	5,569	144.5%
Monmouth	112,128	22.3%	17,533	29.5%	4,262	76.8%
Morris	62,582	15.4%	18,886	53.0%	2,954	79.9%
Ocean	164,878	47.6%	41,498	57.8%	11,103	291.3%
Passaic	41,464	9.3%	6,294	11.9%	3,022	64.6%
Salem	-391	-0.6%	1,817	24.2%	450	70.1%
Somerset	94,361	46.5%	15,179	83.4%	2,164	110.1%
Sussex	28,047	24.2%	3,031	29.9%	627	62.8%
Union	18,447	3.7%	7,550	11.7%	4,303	84.9%
Warren	18,008	21.3%	2,754	26.3%	561	49.6%

Table 5. New Jersey License Rates by Age - 2000

	Licenses	Population	Ratio of licenses
Age			to Population
55-64	713,350	753,984	0.946
65-74	496,908	574,669	0.865
75-84	319,262	402,468	0.793
85 +	67,128	135,999	0.494

However, the number of old old drivers is likely to increase in the future as more people live longer. Further the rate of being licensed among the older age categories, as well as the number of people, will increase in the future, because people born more recently obtained licenses at a higher rate than in their parents generation. The data that might show the increasing rate of licenses among the older population is not available for New Jersey, but Table 6 provides comparable information for New York State. (Note that the rate at which people have licenses in any age group is lower in New York than in New Jersey; this is probably due to the influence on New York City (where many people do not own cars or drive) and to the lower incomes on average in New York State.) In the six year period shown, the increase in the rate of being licensed grew substantially (excepting the idiosyncratic low growth for the 65 to 69 group) from 3.5 percent for the 50 to 59 year olds to 28.6 percent for the 80 and over age group. It is likely that the high growth license rates for the older age groups will occur in New Jersey in the next decade.

Table 6. New York State License Rates

	Ratio of licenses		Rate of
	to population		growth
Ages	1993	1999	'93 to '99
50-59	0.798	0.825	3.50%
60-64	0.738	0.774	4.90%
65-69	0.717	0.722	0.70%
70-74	0.675	0.707	4.80%
75-79	0.590	0.656	11.20%
80+	0.353	0.454	28.60%

REVIEW OF THE LITERATURE

The Problem And Overview Of The Literature Review

The issues of safety and mobility of older drivers stem from demographic increases in the older segment of the population and their increased risk for injury or death in an automobile crash when compared with younger segments. During the decade of the 80’s, the proportion of drivers in the older category grew at a greater rate than all other licensed drivers.^(7,8) Barr⁽⁷⁾ observed that between 1989 and 1999, the number of older licensed drivers increased 39% to 18.5 million. In the same time period, the total number of all licensed drivers increased 13%. Hu et al⁽⁸⁾ found that from 1985-1995, the number of drivers’ licenses issued to over-60 drivers increased 22% with the greatest increase in the over-70 driver age group. Moreover, these older drivers were driving more miles. When crash rates are based on mileage, drivers over the age of 85 have the highest fatality rates of all age groups.⁽⁴⁾ The actual rate for males over the age of 85 was 10 fatalities per 100 million vehicle miles traveled. In comparison, the rate for males age 40-44 was less than 1 per 100 million vehicle miles traveled.

Interest in older drivers is not a new phenomenon. Hakamies-Blomqvist⁽⁹⁾ noted a history dating to the 1930’s. Then, drivers were often considered older after reaching 40. Whatever the dividing point, research on older drivers from the perspective of “crash risk” almost always uses chronological age. Hakamies-Blomqvist points out that chronological age is convenient but aggregates drivers with varying abilities. Use of chronological age presents problems when it comes to developing policies regarding older drivers. Thus the first area reviewed in the literature is the various ways crash risk is defined.

Regardless of the measure used to generate crash risk, the risk is an average for the entire age group. Yet, there is variance in how abilities related to driving are distributed within age groups. To safely operate an automobile, drivers need to perceive information about road conditions, other drivers, weather conditions and their own vehicles. This information needs to be effectively processed and appropriate responses need to be made quickly and accurately. The factors primarily involved in the perceptual and reaction processes are visual, cognitive, and psychomotor abilities. Health factors clearly have impact on the previously mentioned abilities and those most closely associated with driving are also reviewed

This literature review begins with definitions of crash risk, then provides descriptive information regarding older drivers and the types of accidents in which they are involved. Also considered are factors associated with driving ability, techniques for assessing driving abilities, and ways to compensate for ability decline. Finally, this review looks at policy issues regarding licensing of older drivers.

Crash Risk Defined

The numbers present varying pictures of risk that older drivers exhibit. Risk is typically defined as the number of accidents/exposure. Typically, measures of exposure become the problematic factor in the measure.⁽⁹⁾ Databases for accident statistics are kept by several government agencies. The denominator or exposure however, has varying approaches to its measurement. While it would be useful to have the population of licensed drivers by age category, these data are often not available. A surrogate measure is often the population in the age categories. If fewer drivers were actually driving in older age categories compared to the totals in the age group, then data regarding crash risks would be biased and underestimated for older categories. (The decision to stop driving is reviewed later.) When exposure is measured using accidents per capita or per licensed driver, the data reveal that older drivers have fewer accidents than other age categories. As Hakamies-Blomqvist points out, if the concern is general cost to the society, then using this type of risk is acceptable.

However, when risk is defined in terms of miles driven, a dramatically different picture regarding risk and older drivers is revealed. The driver fatality rates per miles traveled, as seen in Figure 1, reveal that older drivers and particularly, very older male drivers (over 85), have the highest crash risk of all demographic groups. This measure is more descriptive of costs to the specific age group. Janke⁽¹⁰⁾ however, reports that a crash per vehicle mile traveled (VMT) tends to exaggerate the crash risk of low-mileage drivers. She explains that high mileage drivers typically gather their VMT on freeways and these are generally safer roads with less exposure to situations that present crash risk (e.g. intersections). Low mileage drivers (into which older drivers group) more frequently travel on local roads and therefore face more potentially pernicious driving situations.

Yet a third measure of exposure is “time” in traffic. Chipman^(11,12) using time and mileage data in a Canadian study, demonstrates lower crash risk for older drivers when time is used than when mileage is used. Since each of the measures presents its own problems, it is important to be aware of the potential biases that are introduced.

Some Dimensions Of The Issue Of Older Drivers

Crash Risk of Older Drivers

The accident propensity of older drivers has received much interest in recent years. Studies of their risk, while primarily focused on older US drivers have also looked at drivers in the U.K., Sweden, Finland, and Australia. A review of the studies shows similar findings. Stamatiadis and Deacon⁽¹³⁾ examined Michigan accident records from 1978-1988. Their measure of accident propensity was

based on a ratio of a particular type of at–fault drivers in a specific condition (e.g. females at fault at intersections) compared to the same type and condition not

Figure 1: Driver Fatality Rates by Age and Sex, 1996

(From Traffic Safety Facts 2000: Older Population.⁽¹⁾)

at-fault. The authors note that this measure is useful when direct exposure estimates are not available. Their data revealed that middle-aged and female drivers were, overall, the safest. Older drivers were found to be the least safe, however, there were cohort and gender effects. That is, younger cohorts of older drivers were less likely to be at fault in an accident than older or more distant cohorts. Gender interacted with age in accident propensity; females were safer drivers than males for the younger age groups but were less safe than males for the older age groups. A cohort effect was also obtained in a 1999 study of Finish drivers.⁽¹⁴⁾ The researchers metric for accidents was the number for the age/gender group as a proportion of the total accidents in that category. For the 60-79 age group, male drivers showed a decrease in intersection accidents in successive cohorts. More specifically, drivers who fell into the age category of 60-69 in 1995 had a lower rate of intersection accidents than those who fell into the same age category in 1987. This did not hold for the 80+ male drivers who showed an increase with successive cohorts. Female drivers showed a decrease for successive cohorts aged 60-69, and no change for the 75+ cohorts. However for both male and female drivers, accidents at intersections increased with age.

Using a 1991 Wisconsin accident database and linking data from two-car accidents to hospital discharge information, Dulisse⁽¹⁵⁾ found that drivers age 65-74 did not impose “excess risk of either death or injuries” to others. (Dulisse looked at both deaths and hospitalizations for varying age groups per 100 million driver miles.) However, drivers 75 and over were associated with increased risk but it was small (1%) in terms of the total number of serious injuries. In another study using data from 1989-1992 for property damage and injuries (fatal and non-fatal) in accidents reported to police in Western Australia, Ryan, Legge and Rosman⁽¹⁶⁾ examined age and gender differences in crash involvement rates. Population data were used to determine the rates for crash involvement. The highest rates of involvement were for drivers 25 and younger (35%) while drivers 70 and older accounted for 3%. However, when distance traveled was factored in, the involvement rates looked similar for the youngest and oldest groups. Drivers over 75 had more direct and indirect right angle crashes and crashes associated with turning movements. Drivers over 75 were more likely to have crashes that resulted in fatalities and hospital admissions. Increased fragility of the older drivers is a frequent explanation.

Types Of Accidents

Looking at the problem of older drivers from the perspective of accident type, Richardson, Kim, Li, and Nitz⁽¹⁷⁾ examined accident data in Hawaii for 1991 and 1992. More specifically they looked at head-on, rear-end, broadside, sideswipe, and rollover crashes. For each type, they classified each vehicle in two-car crashes as being either the car that initiated the strike or the car that received the strike. They report that head-on and rear-end initiations, and rollover crashes decrease with age. But older drivers are more likely to be involved in crashes where they broadside or sideswipe other vehicles. They are also more likely to be broadsided or sideswiped. From the types of crashes they are involved in, Richardson et al infer that older drivers are more likely to be in crashes that involve driver error rather than poor judgment. Errors might be observation failures regarding traffic signals and other vehicles. An interaction was obtained between age and gender. Older females are more likely to be involved in headoners and sideswipers than older males and less likely to be rearended.

McGwin and Brown⁽¹⁸⁾ looked at crash types and age using 1996 data from Alabama. Their findings reveal that older drivers were more likely to be involved in crashes at intersections, in failing to yield right of way, to obey stop signs and signals, and with objects they did not see. They were less likely to be involved in accidents that were associated with driver fatigue, during early morning and evening, during bad weather, traveling at high speeds, on curved roads, and involving a single vehicle. McGwin and Brown infer that older drivers’ accidents reflect problems in perception, judgment, and responding to traffic conditions. This is similar to the driver error inferred in the Richardson, et al study.⁽¹⁷⁾ McGwin and Brown⁽¹⁸⁾ also obtain interaction effects between age and gender for fault. While males were more likely to be the responsible party in accidents involving younger drivers, females were more likely to be responsible among older drivers. A similar result for female drivers was obtained by Stamatiadis⁽¹⁹⁾. When the number of drivers determines crash rates, males have higher crash rates but when the criterion is personal miles traveled, females display higher rates except for the youngest drivers. If only fatalities are considered then males display higher rates.

Hu et al⁽⁸⁾ summarized findings which used crash data from North Carolina. In general, older drivers were increasingly at fault when two cars were involved. That was particularly the case for left-turns, right-turns and straight ahead angle crashes. Older drivers had problems at non-signalized intersections when compared to younger age groups.

Using an experimental approach, Dobbs, Heller and Schopflocher⁽²⁰⁾ compared driving skills in a controlled situation for three groups of drivers: older drivers with clinically significant declines, normal older drivers and normal younger drivers. Expert driving evaluators also evaluated them. Their results indicate that the category of hazardous errors distinguishes best among the groups. Hazardous errors were those that were obviously dangerous regardless of the type of maneuver and either required the driving evaluator to take control of the car or forced traffic to adjust to accommodate the error. Other errors that discriminated between safe and unsafe drivers were minor positioning errors (too close to lane markings), turning positioning errors (wide or cut turns), and scanning errors (no shoulder checks). Such information could be useful in screening procedures for licensing of older drivers, particularly those with cognitive impairment.

National Statistics Regarding Fatalities In Automobile Crashes

In 1999, older drivers (70+) accounted for 5% of all injuries in traffic crashes.⁽⁴⁾ however, older drivers accounted for 13% of all traffic fatalities. While in absolute numbers driver fatalities have increased markedly from 1989 to 1990 (46%), driver involvement rate per 100,000 drivers, shows a decrease and a leveling for older drivers. Rather consistently, older drivers fatalities occur during daylight, on weekdays, and involve another vehicle. When the accident involves both a younger and an older driver, the older driver is far more likely (59%) to be struck than the young driver (19%). In these two car crashes, both cars are likely to be proceeding straight ahead at the time of the collision, but in 27% of the cases, the older driver was making a left turn. The propensity for left turn intersection crashes was seven times higher for older drivers than younger drivers in 1999 and eight times higher in 1998. Older drivers in fatal crashes have the lowest proportion of intoxication of any adult driver age group.

Factors Associated with Driving Abilities

Operating an automobile requires an array of perceptual, cognitive and motor abilities. Information about other cars, road conditions and the automobile being driven must be discerned, processed and responded to quickly and accurately. This involves visual and perceptual factors, cognitive factors and psychomotor factors. All of these are sensitive to age-related declines. Beyond age related declines is the impact of medication that frequently increases among older citizens. Eby, Trombley, Molnar and Shope⁽²¹⁾ presented a comprehensive review of these factors in their 1998 report. The following section summarizes and updates their review.

Visual Factors

In a review of visual requirements for driving safety, Shinar and Scheiber⁽²²⁾ propose that vision is responsible for 95% of driving-related information inputs. Charman⁽²³⁾ notes that hearing is a second contributor but far below vision in importance. It would seem to reason that if good vision is necessary for safe driving, then poor vision is at least a pre-cursor to unsafe driving. Both Shinar and Schieber⁽²²⁾ and Charman⁽²³⁾ have noted however, that there is a weak positive correlation between increase in deteriorated vision and increases in unsafe driving. Shinar and Schieber reason that this weakness is due to several factors. In summary, accidents have multiple causes; typically, causes of accidents are cognitive such as distraction and misjudgments; vision-screening tests may be unreliable; more reliable tests of vision are not in widespread use; and drivers may compensate for deteriorated vision by restricting their own driving. Nonetheless, several aspects of vision have been studied in relation to driving. These include: static visual acuity, dynamic visual acuity, motion perception, contrast sensitivity, color vision, night vision and glare accommodation, visual field and useful field of view.

Static Visual Acuity

Static visual acuity deals with the ability to perceive details at a given distance, such as being able to read road signs. Static visual acuity is usually measured by the Snellen (letter) chart. In the United Kingdom the visual requirement for a driver’s license is the ability to read a license plate in daylight (with corrected vision) at a distance of 67 feet.⁽²³⁾

Clearly static vision deteriorates noticeably after age 40 or 50.⁽²¹⁾ However, the relationship between visual acuity and safe driving is unclear. Charman⁽²³⁾ citing a Hills and Burg study in 1977 points to the very low correlation between visual acuity and accidents (<0.10) and only for drivers over 54. Since the tests have high contrast between the image of the letter and the background, these tests may not be sensitive to situations found in the field where contrast is not strong. Wood⁽²⁴⁾ used binocular visual acuity for a sample of young drivers, older drivers (age 60+) with normal vision and older drivers (60+) with early impairment. All were legally eligible to drive in Australia. Driving ability was tested on a closed circuit course and measurements were made of errors in sign detection, central and peripheral reaction time, driving time and errors in speed estimation. Results indicated that all older drivers had poorer sign recognition ability and peripheral reaction time. Driving time was also slower for older drivers. Those drivers with early vision impairment performed even more poorly than those with normal vision. Since all drivers were legally eligible to drive and were frequent drivers, this research demonstrates the negligible prediction value of standard tests of high contrast visual acuity. Dunne⁽²⁵⁾ is exploring low contrast visual acuity as an indicator of accidents.

Dynamic Visual Acuity

Dynamic visual acuity (DVA) deals with the ability to perceive details of a moving target. It is measured moving a Snellen letter across the horizontal plane of the observer. Shinar and Schieber⁽²²⁾ refer to Burg’s 1964 finding that dynamic visual acuity has stronger association with accident involvement than static acuity.

Motion perception

Motion perception is the ability to detect an object’s movement from one location to another. This is another process that deteriorates with age and older adults require more movement for detection than younger ones.⁽²¹⁾ Shinar and Schieber⁽²²⁾ cite studies that link decrements in motion perception to accidents. Moreover, Eby et al.⁽²¹⁾ conclude from their review that older drivers may be slower in perceiving critical movement in traffic situations. This would provide less time for older drivers to react.

Contrast sensitivity

Contrast sensitivity is the ability to detect detail in gradually diminishing contrast to the background. Charman⁽²³⁾ reports that contrast sensitivity does correlate with driving performance. Eby et al⁽²¹⁾ refer to work by Schieber in which he found that declines in age-related contrast sensitivity are associated with increased frequency of self-reported vision problems in driving. However, there is no strong link yet established between contrast sensitivity and accident propensity.

Color Vision

Color vision defects are not thought to hinder safe driving.⁽²³⁾ However, inability to recognize traffic signals does slow reaction to them. Whillans and Allen⁽²⁶⁾ advise that drivers with color vision defects maintain greater distances between vehicles. Charman also notes in his review that drivers with red color vision defect need four times the normal intensity to detect a red light. Some age related changes in color vision also occur due to changes in the lens. Lighthouse International reports on its website that blues and greens may become more difficult to distinguish. Macular degeneration which is age related also affects color vision.

Night Vision And Glare

Night driving requires an additional set of visual abilities beyond day driving. It requires acuity in low light, as well as resistance and recovery from glare caused by on-coming cars. Eby et al⁽²¹⁾ synthesize research on illumination and aging and document that anatomical changes to the eye over time result in decreased sensitivity to light. This translates into older drivers needing significantly more light than younger drivers to see well. In daylight, the light is sufficient but at night, older drivers require brighter lights than younger drivers. Shinar and Schieber⁽²²⁾ discuss the effect of glare on vision in relation to aging. In general, glare interferes with vision. The effects of glare get worse with age. Despite the difficulties glare produces, the relationship between glare and crash risk is not well established.

Visual Field

Visual field is the area in which vision is possible with eyes held in a fixed position. Charman⁽²³⁾ notes in his review, that monocular field loss was not associated with accident involvement but that the accident rates for drivers with binocular field loss were twice the rate of drivers with normal fields. Moreover these drivers were unaware of their peripheral vision problems. Wood and Troubeck^(27,28) have studied the impact, experimentally, of reduced visual field. They use goggles to restrict the field and found that driving performance using a simulator was significantly worse with restricted fields. The effect was heightened when the subjects were older drivers. Similar to what Charman reported, Wood and Troubeck did not find decrements in driving performance with only monocular field restriction.

Eye Movements

The eye’s ability to resolve detail is not uniform. In the center of the retina is a region with densely packed receptors that allows for fine resolution so that when we look directly at an object, we get the best image of it. However, objects move and so does the observer. Our ability to keep an object clearly in view depends on eye motion know as saccadic eye movements. These are quick eye movements that function to keep the image in the center of the retina for continued good resolution. Eby et al⁽²¹⁾ review literature on eye movements which indicates that in comparison to younger individuals, older adults take longer to begin saccadic movements and take more saccadic movements to keep an object in focus. This suggests that older adults may require more time to locate objects in their visual field. Maltz and Shinar⁽²⁹⁾ examined eye movements of older and younger drivers using computerized simulation of the view from the driver’s seat. Their findings show that older participants had longer search times than younger participants and that they had shorter saccades (eye movements) with more fixations (stopping to look). They also found that older adults scanned a smaller portion of the scene and would review it or go back to relook in comparison to younger adults who tended to scan scenes more evenly. Thus, it appears that with age, the scanning strategy loses efficiency.

Eby et al⁽²¹⁾ also reviewed research on tracking moving objects and the extent of upward and downward gaze. Findings on pursuit (tracking) eye movements shows that older adults track more slowly than younger adults and have a smaller range of upward and downward gaze. Combined, these results indicate that older adults would have to initiate more head movements to see the entire contents of a relevant visual field than would younger adults. This adds time to the task of driving.

Useful Visual Field

Ball, Owsley and their associates^(30,31,32) have pursued the relationship between useful field of view and driving accident propensity over a number of years. This process examines the driver’s ability to simultaneously process information from central and peripheral visual fields similar to what occurs behind the wheel. The task involves looking at a visual display screen and identifying a central objects such as a car or truck and locating a peripherally displayed object which can be located in any of 24 various locations. Introducing visual distractions in the form of triangles can complicate the task. Ball, Owsley and their associates claim that if drivers cannot identify both central and peripheral targets, then they cannot adequately divide their attention between both fields as is needed for driving safely.

Using a sample of 294 subjects ranging in age from 60-85, Owsley et al⁽³²⁾ measured visual acuity, contrast sensitivity, visual field sensitivity, useful field of view, and mental status. All subjects underwent a comprehensive eye examination and medical conditions and medications were noted through a self-report questionnaire. Motor vehicle crash records for these subjects were tracked for three years following vision measurements. Fifty-six of the subjects had a least one crash during the 3-year period and 11 had at least 2 crashes. Of the various visual measurements used only useful field of view discriminated between those who experienced a crash and those who did not. Their finding reveal that older drivers with a 40% or greater reduction in the useful field of view were 2.1 times more likely to have had a crash. On the other hand driving less than 7 days a week was associated with a lower risk for crash involvement.

Visual Impairment And Driving.

Several studies which examine the effects of age and driving also considered visual impairment. Szlyk, Seiple, & Viana⁽³³⁾ examined a sample which varied in terms of age (younger and older) and vision (normal and impaired). Vision was measured using a test of visual field and driving through an interactive simulator. Self-reports were taken regarding accidents. Simulator driving speed decreased for all older subjects and for younger subjects who had visual impairment. Older subjects also took longer for braking response time and had more lane boundary crossings. Finally age was also related to having accidents on the simulator course. For the major measures, age had an impact but visual status did not. Yet for the self-reports, younger subjects reported more accident involvement than older subjects. Szlyk believes compensatory factors account for the discrepancy. Older subjects drive more slowly, take fewer risks, and have more eye movements than younger subjects. The increased eye movements alone may not be a compensatory strategy but could be reflective of cognitive hesitancy and the need to confirm detected objects.

McGwin, Chapman, and Owsley⁽³⁴⁾ examined self-reported driving difficulties and visual functions among drivers aged 55 to 85. This sample was selected from ophthalmology practices and optometry clinics. Seventy-five percent of the sample had cataracts and the rest were cataract free. Subjects were measured for visual acuity, contrast sensitivity, glare disability, and useful field of view. In addition cognitive functioning was evaluated. Driving habits were measured by self-reports. The questionnaire was administered by interviewers and probed areas such as difficulty in driving in bad weather, congested traffic, alone, left turns, etc. Decreased visual acuity was associated with reported difficulty in night driving and on high traffic roads. Decreased contrast sensitivity was associated with more difficulty in making left turns, and those with decreased useful field of view reported more problems with driving in the rain.

Cognitive Factors

Cognition includes acquiring, processing, storing and retrieving information. Two particularly relevant processes are those of attention and memory. Attention, the process of focusing momentary awareness on a particular situation, is critical to safe driving. Driver distraction, a state when attention is diverted from driving tasks to irrelevant ones, is receiving a great deal of attention in the public media and in various local legislatures as they consider banning hand held cell phone use while driving. Cell phone activity is only one of many factors that detract from drivers’ focusing attention on the road. Lack of attention results in actually not perceiving or misperceiving important road situations or vehicle situations. As a consequence, the driver either fails to make a maneuver, makes the maneuver too late, or makes an inappropriate maneuver.

Attention:

For the purpose of dealing with attention and driving, three processes are pertinent: vigilance or sustained attention, divided attention which is the ability to deal with two sources of information and two tasks simultaneously, and selective attention, which involves picking out relevant information and suppressing attention to irrelevant information.

Eby et al⁽²¹⁾ conclude from their summary of research that the relationship between vigilance and crash risk is not reliably established and that age differences in the ability to sustain attention have not consistently been found. Mounting evidence from studies on distraction will contribute to greater understanding of the role vigilance plays in crash risk.

Driving involves dividing attention between numerous sources of information, some relevant to the task and some unrelated but nonetheless attention grabbing. Drivers need to monitor the flow of traffic and attend to their own speed and driving maneuvers. Drivers also engage in “off-task” activities while driving such as conversing with passengers, talking on cell-phones, adjusting the radio, tape, and CD controls, and day-dreaming. Eby et al⁽²¹⁾ review research on age and divided attention which points toward a negative relationship between the ability to divide attention and age. It should be noted that dividing attention increases the mental load and thus decreases performance for all ages. In fact, Sekuler, Bennett, and Mamelak⁽³⁵⁾ examined changes with age in useful field of view (UFOV) which requires dividing visual attention between central and peripheral tasks, as a function of age and found that decline in UFOV begins as early as age 20. Brouwer, Waternink, Van Wolffelaar and Rothengatter⁽³⁶⁾ found that older drivers performed more poorly than younger ones during a driving simulation task which required divided attention between lane tracking and counting dots. When older drivers encountered the dot counting task, their lane tracking became significantly poorer. Similarly, their dot counting also showed more inaccuracies. Interestingly, older drivers made fewer errors in dot counting when they could responded vocally then when they had to respond manually. This suggests that in designing controls, no mode for control (e.g. voice, hands, feet) should be overloaded.

Finally, as stress increases, for instance, from increased traffic congestion or complicated maneuvers such as left turns, attentional focus narrows which should narrow the useful field of view. As UFOV constricts, there is more propensity for accidents. Janelle, Singer, and Williams⁽³⁷⁾ found among a sample of college students that performance declines were experienced in both central and peripheral visual tasks at higher levels of anxiety. They also noted eccentric search patterns with an increase in distraction.

Selective attention requires that relevant stimuli receive focus, while irrelevant ones be ignored. Applied to driving, drivers need to screen out irrelevant information and stimuli and focus on the task of driving. Eby et al⁽²¹⁾ found that there is a negative relationship between selective attention ability and crash risk. Moreover, selective attention ability appears to decline with age.

Memory:

Human memory is composed of working or short term memory (STM) which is limited in capacity and which engages in active processing, and long term memory (LTM), which theoretically has unlimited capacity and is the storage reservoir. Eby et al’s review⁽²¹⁾ of age and STM indicates that not only does STM show decrement with age, processing time for accessing information also increases with age. They cite research by French et al⁽³⁸⁾ which links hesitancy in decision making with crash risk. Radeborg and Briem⁽³⁹⁾ investigated the impact of driving on working memory. Using a simulated driving situation, they found that driving interfered with both recall and judgment of verbal material. That is, as driving added to mental load of working memory, attentional resources were siphoned off from a verbal task. Long term memory also has age related decrements. Studies⁽²¹⁾ indicate that with age, there is greater difficulty retrieving information. Combining slower processing speed with slower retrieval time, older drivers are at a disadvantage particularly as driving conditions add to information overload.

Psychomotor Factors

Driving is a task, which requires the ability to coordinate and move various parts of the body in relation to sensory inputs from the environment. One critical component of psychomotor abilities is that of reaction time. This involves the lapse of time from onset of a stimulus to completion of a physical response, such as the time it take to brake a car in response to a traffic signal. Eby et al’s literature review⁽²¹⁾ clearly presents evidence of the decline of reaction time with age. Further, they present findings that indicate that the slowing of reaction time with age is due more to central processing and decision making than to actual time it takes to make a movement. Hesitancy about what to do increases the reaction time not slowness of movement once the decision has been made about what to do.

Intersection navigation presents a driving situation that calls for an increase in coordination of response to a complicated visual scene. Keskinen, Ota, and Katilu⁽⁴⁰⁾ looked at the driving behavior of older drivers moving through intersections. While their results showed no difference in attentional behavior as measured by head movements, they did find variations in acceleration and the time to move through intersections which were related to age. From previous studies on reaction time, it seems that the slowing down comes in the central control process as sensory information is dealt with and a decision needs to be made about the best way to proceed.

Health Factors

According to the Center for Disease Control and Prevention (CDC) and National Center for Health Statistics (NCHS) life expectancy in the United States has increased since 1990 and 80% of all Americans are expected to reach the age 65 years and live longer in this millennium.⁽⁴¹⁾ Many of these older people live healthy active lives but Jeffrey Koplan, CDC Director, said that a significant number of people 85 years and over are affected by chronic diseases and disabilities that interfere with their daily activities. Disability increases with age and the percent of disabled people is higher in the 85 years of age and over group than in the 70 to 74 year group. Heart disease, cancer and stroke are the leading causes of death in the United States. Other important causes of death are obstructive pulmonary disease, diabetes, pneumonia and influenza.⁽⁴¹⁾

Driving a car safely is one of the activities that can be affected by these health problems. Diabetes, for example, can damage some nerves in hands, legs or eyes and changes in blood sugar level also occur. Loss of consciousness and dizziness as result of some devices such as automatic defibrillator used to treat some heart disease can interfere with safe driving; stroke is also mentioned among the health problems that affect driving.⁽⁴²⁾

Health problems are more likely to affect older drivers than they affect young drivers.⁽²¹⁾ Additionally, some of the medications that older people use to treat their diseases, frequently more than one at the same time, and the side effects of these drugs can put them at risk while driving.⁽⁴³⁾

This section reviews the findings about the most common medical conditions and medications that affect mature drivers and their impacts on their driving abilities.

Medical Conditions

The likelihood of having diseases such as diabetes, heart disease, arthritis, dementia, psychiatric disorders and others increases with age. More than 80% of people 65 years and older have at least one chronic disease and the majority of them have two or more at the same time.^(44,45) Diabetes mellitus and coronary heart disease, for instance, have been found to be strongly associated especially in older people. Vokonas and Kannel,⁽⁴⁶⁾ in a review of medical literature, described this association as impressive and noted that diabetes can accelerate the process of arteriosclerosis causing a stroke.

Similarly there is a connection between depression and coronary heart disease. Ahto et al⁽⁴⁷⁾ conducted a study in Lieto, Finland, to analyze this relationship using 89 men and 73 women with coronary heart disease matched by age and sex with a control group of 178 men and 146 women free of heart disease; all participants were over 64 years old. The results showed that depression is more frequent in men with coronary heart disease than it is in men free of this disease. For women depression was associated with previous clinical depression, physical disability and the use of angiotensin-converting enzyme (ACE) inhibitors. Ahto et al noted “Possible limitations caused by a severe coronary heart disease on functional abilities may easily trigger a current depression among women who have had previous episodes of depression”

Waller, Naughton, Gibson, and Eberhard (as cited in Janke⁽⁴⁸⁾) found that among 119 patients admitted to hospitals for ischemic heart disease, 43% had hypertension problems, 20% had chronic lung disease, 14% were diabetics, 11% had peripheral vascular disease, 8% cerebrovascular episodes and 8% reduced vision, deafness, and renal disease.

These diseases affect the normal lives of older people including their ability to drive. Schwager⁽⁴⁵⁾ describes crashes among the elderly as a geriatric syndrome derived from chronic diseases along with changes in physiology and patterns of behavior. Odenheimer⁽⁴⁹⁾ lists Alzheimer’s disease, vision problems, stroke, Parkinson’s disease, arthritis, and diabetes as factors for unsafe driving. The National Institute on Aging⁽⁴²⁾ cited arthritis, Parkinson’s disease, stroke, sleep problems and fainting, as examples of illnesses that can interfere with safe driving. In addition, they recommended that people who are at risk of losing consciousness should stop driving. Carr⁽⁴⁴⁾ pointed out that some older people can be safe drivers but others, with physiologic or cognitive impairments such as musculoskeletal disorders, sensory disorders, dementia, psychiatric disorders, stroke, sleep apnea, and alcohol and illicit drug use, put themselves and others at risk while driving.

Zhang et al⁽⁵⁰⁾ analyzed and quantified the relationship between possible risk factors and the severity of crashes involving elderly drivers in Ontario between 1988 and 1993. The database included accidents in which at least one driver was 65 years or older. Diabetes mellitus, chronic heart disease, epilepsy, amputations, vision disorders, and hearing loss were mentioned in the written police reports. The study also found that risk from these conditions increases as the age increases; drivers aged 80 and over are more likely to have these conditions than drivers 65 to 69.

McGwin et al⁽⁵¹⁾ conducted a population-based case-control study to analyze the connection between chronic medical conditions and at-fault crashes involving older drivers. Of 901 drivers 65 years and older from Mobile, Alabama who participated in the study, 244 were involved in at-fault crashes, 182 were involved in crashes for which they were not at-fault, and 475 were not involved in crashes. Information on driving habits, driving situations and types of vehicles was collected by telephone interviews and previous crash histories from 1991 to 1995 was obtained from the Alabama Department of Public Safety. The results of this study show that “several medical conditions and medications were associated with the risk of crash involvement among older drivers” (p. 430). Heart disease and stroke showed significant connection with the crashes; drivers with these diseases were more likely to be involved both in at-fault and not-at-fault car accidents than drivers free of these diseases. The researchers⁽⁵¹⁾ also noted that several previous studies have established a relationship between heart disease and car accidents. The researchers further noted that arthritis and diabetes increase the risk of being involved in a car crash especially for female drivers.

Heart Disease

Coronary Heart Disease is the leading cause of death in the adult population in the United States.^(52,41) The risk of coronary heart disease increases with age; approximately four out of five people who die of this disease are 65 years and older. Coronary Heart Disease is responsible for 50% of all deaths in people 65 years and over.^(53,54) For people 75 years and over, coronary heart disease causes 70% of all deaths. For people 85 years and over, coronary heart disease are responsible for 58% of the mortalities.⁽⁵⁴⁾ In a study to analyze different predictors of heart disease, Chen and colleagues⁽⁵⁵⁾ evaluated 1,749 people 65 years and over who had not had heart problems before the study. Participants were followed from 1982 to 1992 and 10% of them developed heart failure. The researchers concluded that older age increases the risk of heart failure.

Since sudden, unexpected death can occur as a result of heart disease the effects of heart disease on driving raises some concern about the risk that people who have any heart disease and drive may pose to society and themselves. Patients with arrhythmia (irregular heart beat), for example, risk personal and public safety while driving.⁽⁵⁶⁾ Sudden death and loss of consciousness are the most common complication among drivers and one of the most frequent causes of driver incapacity.⁽⁵⁷⁾ In a conference held in Washington, DC., in 1995 to discuss the growing issue of arrhythmias, driving and other activities, attendees found limited amount of data available about this issue.⁽⁵⁶⁾ One of the reasons for the limitation of data could be that for medical information to be released the authorization of the patient is required and in some cases of motor vehicle accidents there is uncertainty if a medical condition was the cause of the accident. However, at this conference it was pointed out that for interstate commerce “It is the intent of the Federal Motor Carrier Safety Regulation to disqualify a driver who has a current cardiovascular disease which is accompanied by and/or likely to cause symptoms of syncope, dyspnea [abnormal or uncomfortable breathing], collapses, or congestive heart failure.” But the final decision will be made by the medical examiner and the motor carrier.

Patients who have an implantable cardioverter-defibrillator (ICD), a device used to treat ventricular tachyarrhythmias, constitute a critical group since this device is implanted into patients who have high risk of having an arrhythmia. Finch et al⁽⁵⁸⁾ conducted a study to evaluate the driving habits of patients with ICDs to see how their driving abilities were affected. They surveyed 105 patients with a mean age of 61 years old. All patients had received the ICD implant at the Medical University of South Carolina. Even though these patients were advised not to drive, 77% of them had resumed driving within 0-24 months; 67% had resumed driving three months after the implant. Forty-nine percent of the patients said that they had at least one shock, three of the patients had the shock while driving. During the shock episode, patients experienced dizziness and loss of consciousness, which are considered risk factors for safe driving. In a conference in 1991 of the American Cardiovascular Society to discuss the issue of heart disease and driving, the participants concluded that patients with ICDs may resume driving one year after the implant if there has not been a shock episode during that time.⁽⁵⁸⁾ In other countries, Great Britain, for example, patients have to stop driving and relinquish their drivers’ licenses once they have an ICD implant. The conclusions of Finch and her colleagues is that patients who do not experience any symptoms after the ICD implant could be allowed to drive but patients who experience persistent symptoms should not be allowed to drive. Curtis and colleagues⁽⁵⁹⁾ evaluated the driving safety of patients with implantable cardioverter-defibrillator. They surveyed 742 physicians about their patients’ fatal and nonfatal accidents. Also, physicians were questioned about recommendations they give to their patients about driving and their knowledge of state driving laws. The response rate was 61. Twenty-five physicians reported 30 motor vehicle accidents related to shocks from 1980 to 1992. Nine of these accidents were fatal, and 21 were nonfatal involving 15 patients, 3 passengers and 3 bystanders. The conclusion of these researchers was that a driving restriction for a short period of time should be recommended to the patients but excessive or total restriction might not be necessary. Jung and colleagues⁽⁶⁰⁾ conducted a study of the European experience of driving after ICD implantation to estimate the risk of death and injury and to make recommendations about patients and fitness to drive. The frequency of the arrthymia, the probability of recurrence and the probability of accidents as a result of these factors were analyzed. These researchers also had the problem of the limited data availability. They concluded that patients who had prophylactic ICD implantations should be allowed to drive for private purposes but commercial driving should be restricted. All other patients should be restricted initially; those without recurrences of ventricular tachyarrhythmias for six months after the implant could resume driving but patients with high risk and recurrences of unstable ventricular tachyarrthymia should have total restriction.

In the opinion of Petch,⁽⁵⁷⁾ Chairman of the U.K. Medical Advisory Panel on Cardiovascular Disease and Driving, “Any disease capable of exposing an applicant for a first license or a driver applying for a renewal to a sudden failure of the cardiovascular system such that there is a sudden impairment of the cerebral functions constitutes a danger to road safety”(p.1175).

Researchers in Ontario, Canada⁽⁶¹⁾ conducted a study to determine the impact of the legislation of mandatory physician reporting for cardiac patients on motor vehicle accidents related to morbidity and mortality. Data were obtained from the Ontario Ministry of Transportation and all drivers with license suspension in 1996 due to cardiac disease participated in the analysis. Researchers found that only 994 licenses were suspended for cardiac reasons when approximately 72,407 licenses should have been suspended according to the legislation. As a consequence, only one death or serious injured was avoided when 29.2 events could have been avoided if the legislation had been followed. The study shows that physicians were not complying with the legislation and researchers concluded that “Mandatory Physician Reporting of patients with cardiac illness has a negligible impact on MVA related to morbidity and mortality”⁽⁶¹⁾ (p. 1257).

Syncope

A syncope is a temporary loss of consciousness due to a temporary reduction of blood circulation to the brain.⁽⁶²⁾ Emotional stress, changes in body position, low blood pressure and heavy sweating are factors that may cause syncope. Syncope is considered “one of the most common, and at the same time, one of the most perplexing of problems that the medical practitioner is called upon to evaluate.”⁽⁶³⁾ Kou et al (as cited in Bänsch et al⁽⁶⁴⁾) consider that age, gender, or previous syncope do not predict syncope. Eby et al⁽²¹⁾ cited other researchers (Bonema and Maddens,1992; Kapoor, 1994) who stated that syncope is very common in older adults; and Savage (1985) who said that at least 3% of the adult population has had at least one syncopal episodes.

According to Olshansky and Grubb,⁽⁶⁵⁾ data establishing the relationship between syncope and driving are difficult to obtain because patients who suffer a syncopal event while driving may report a different factor as the cause of the accident. This occurs due to the confusion that follows an accident or sometimes because of fear that their driver licenses may be revoked. The researchers point out that it is hard to determine when an individual passes out or goes to sleep behind the wheel. At the same time, the risk posed for patients with syncope seems to be small and other factors such as the frequency and length of driving may also influence this risk. However, they state that “syncope appears to be a significant cause of serious driving accidents in the elderly” (p.375) and that “individuals who experience recurrent unpredictable period of loss of consciousness, but who continue to drive, risk not only their own lives but the lives of others as well” (p.372). They⁽⁶⁵⁾ cited an earlier study, Rehns et al. (1995), which evaluated drivers involved in road crashes over a one year period. There were 84 elderly drivers and 67 of them were in at-fault accidents. Twelve of these accidents were believed to be due to syncope.

Bänsch, et al⁽⁶⁴⁾ conducted a study to evaluate the occurrence, risk prediction and prevention of syncope in patients who had received an implantable cardioverter-defibrillator (ICD), a device used to treat ventricular tachycardia (VT) and fibrillation (VF). The researchers analyzed information such as clinical history, outpatient chart reviews and episode events of 421 patients; 229 (more than 54%) had recurrent VT/VF and 62 (almost 15%) had syncope. The analysis showed that after the implantation, the survival rate free of VT/VF was 58% during the first year, 45% during the first two years and 37% during the first three years. For syncope the survival rate was 90% during the first year; 85% in the second year and 81% in the third year. The researchers found that syncope as a result of ICD implantation is very common, most often occurring soon after the implantation. The highest risk (10%) is found during the first year going down to five percent during the second year; it is still significant in the third year. Researchers concluded “that once patients had a VT recurrence, syncope during the first VT and a high VT rate were the strongest risk predictors of future syncope” (p.608). One patient in this study had syncope while driving a car and died shortly after the syncope, but a passenger in the front seat prevented an accident.

Personal injury, property damage and even death can be consequences of having a vasovagal syncope while driving according to a study conducted by Huagui et al.⁽⁶⁶⁾ From March 1990 to May 1996, Huagui and his colleagues from University of Nebraska Medical Center studied 245 patients who had had syncope while driving. The researchers found that once a person has had syncope, the recurrence of another one is very high during the following three to six months; they therefore recommend that driving be restricted for at least three months.

Stroke

A stroke is the interruption of the blood supply to the brain that occurs when a blood vessel or artery is blocked or broken and that causes damage to the brain tissue. The kinds of stroke are thrombotic, embolic, hemorragic, and aneurysm.^(67,68) When a stroke occurs some brain cells die and people lose some abilities partially or totally depending on the seriousness of the stroke, the extent of the brain damage and the part of the brain where the stroke happens (right hemisphere, left hemisphere, cerebellum or the brain stem).⁽⁶⁹⁾ According to the National Stroke Association⁽⁶⁹⁾ intellect, sensation, perception and movement are the abilities most affected by stroke. Stroke is the third leading cause of death in the United States. Approximately 750,000 Americans have a new or recurrent stroke every year, and close to 160,000 of them die.⁽⁷⁰⁾ The same source affirms that almost four million Americans are living with the effects of strokes and approximately one-third of them are mildly impaired, another third are moderately impaired and the rest have severe impairments. Approximately 3% to 10% of stroke survivors will have another stroke during the following 30 days, 5% to 14% within a year and 25% to 40% within five years.

Age increases the risk of having a stroke; for people 55 years and over, each decade doubles this risk. People 65 years and over have a seven times higher risk of dying from stroke than the rest of the population, and two thirds of all strokes happen to this segment of the population. More than 23 percent of the over 65 years old stroke victims die within a year of the stroke.^(70,71) For men between the ages of 65 and 69, the prevalence of having a transient ischemic attack (TIA), which is defined as a mini-stroke that lasts less than 24 hours, is 2.7 percent, rising to 3.6 percent at ages 75 to 79. For women the prevalence is 1.6 percent for ages 65 to 69 and 4.1 percent for ages 75 to 79. Some conditions that are very common in older people, such as high blood pressure, diabetes and heart disease, also increase the risk of having a stroke.^{(See references 68, 71,
72, and 73.)} In the case of hypertension, the risk is four to six times higher than that of the general population.

The National Institute on Aging⁽⁴²⁾ considers stroke one of the illnesses that may interfere with the ability of older people to drive safely. Results of a recent study by researchers at the University of Alabama at Birmingham support this statement. McGwin et al⁽⁵¹⁾ conducted a population-based, case-control study to identify medical conditions and medications that may be related to at-fault crashes involving elderly drivers. McGwin and colleagues studied the1996 driving records of 901 drivers 65 years and older. Of this sample, 244 drivers were involved in at-fault crashes; 182 were involved in crashes but were not-at-fault; and 475 were not involved in crashes. The results show that stroke patients are twice as likely to be involved in at-fault crashes than the control group leading the researchers to conclude that the combination of age-related problems and neurological damage resulting from the stroke may affect the ability of safe driving in older people. Findings also show that arthritis and heart disease affect safe driving abilities.

The American Academy of Family Physicians⁽⁷³⁾ advise that some of the abilities required to drive safely, such as mobility, vision, thinking and reaction time, can be affected by stroke, and that people who have had a stroke are at high risk of having another during the year after the stroke. However, many drivers resume driving after a stroke. Stroke victims who are thinking about resuming driving should be warned that they may compromise their own safety and the safety of others.

Fisk et al⁽⁷⁴⁾ conducted a survey on patients who had been treated after a stroke in the psychology service of a university rehabilitation center from 1990 to 1995. Two hundred ninety (290) people who were drivers before the stroke participated in the study; the mean age was 66 years old. The researchers found that 30% of the patients resumed driving. While some of the drivers limited their driving to three or fewer days per week, others resumed their previous driving habits and were driving six to seven days a week. Approximately 35% were given advice about driving from their doctors, 27% from their families and almost 50% did not receive any advice. In addition, 90% of the participants did not have an evaluation of driving skills after the stroke. The researchers point out that even though their study does not directly address the crash-risk concern in this group of drivers “evidence suggests that stroke survivors have characteristics that elevate their risk” (p.1344). Fisk et al⁽⁷⁴⁾ cite a comparable 1986 study by Legh-Smith et al, which found that 42% of stroke victims who had driven before resumed driving after their stroke.

Janke⁽⁴⁸⁾ cited Jones, Giddens, and Croft (1983) who assessed 300 brain-damaged patients, some who had had a stroke, for driving capability. The researchers found that “while most of the patients performed well in the off-road tests, they were generally unreliable, emotionally unstable, and erratic on the road” (p.86). Wilson and Smith (1983), also cited by Janke,⁽⁴⁸⁾ evaluated patients who had had a stroke but were considered ready to drive by their doctors. When given a road test these patients had problems entering and leaving the highway and reacting adequately in emergency situations. They also had problems trying to align their vehicles with the side of the road. The researchers “call into question the adequacy of driving decisions presumably made on a medical basis alone.” (p.81)

Morgan and King⁽⁴³⁾ said that in the UK all stroke and transient ischemic attack (TIA) patients are immediately suspended from driving for at least one month due to the high risk of the occurrence of another attack, according to the guide of current medical standards for fitness to drive. They cited Noury and Lincoln (1993), who conducted a study of stroke victims who had been active drivers before the stroke. The subjects took a road test, which they passed or failed. Then, they were randomly assigned to one of two groups for evaluation. The first group was evaluated using the stroke drivers screening assessment, and the second group was evaluated by their general practitioner. The evaluation results for the two groups were compared to the results of the previous road test. The researchers found that the results of the stroke screening test corresponded with the performance of the road test for 81% of the subjects, while the general practitioners’ evaluation corresponded with the performance of only 56% of the clients. The researchers concluded that “it would appear that the present system allows a substantial proportion of unsafe drivers to resume driving and use of the stroke driving screening assessment would be a cheap and simple improvement on the present system.” (p.527)

Diabetes

Diabetes is a disease that does not let the body convert the food into the energy the body needs to function; it is characterized by changes of levels of blood glucose. This disease is the fourth leading cause of death in the United States. There are two types of diabetes: type I and type II.⁽⁷⁵⁾ The National Institute of Diabetes and Digestive and Kidney Disease⁽⁷⁶⁾ states that 15.7 million people, which constitute 5.9% of the total population, have Diabetes, of which 6.3 million are 65 years and older (or 18.4 percent of this age group). The same source shows that adults with type I diabetes die from heart disease or stroke at 2 to 4 times the rate of people without diabetes. They also state that 90 to 95% of all Diabetes patients suffer from type II Diabetes. Older age is considered a risk factor for this type of Diabetes. Other common conditions in older people, such as heart disease, stroke, high blood pressure, have been found to worsen the condition of diabetic patients. In addition, Davidson, cited in Eby et al,⁽²¹⁾ found that changes in blood glucose concentration as a result of diabetes may result in cerebral vascular accidents, myocardial infarctions, diabetic retinopathy, kidney disease, and peripheral vascular disease.

Since Diabetes affects cognitive functions, there is a concern that it may put diabetic patients who drive at a higher risk of being involved in a crash than the rest of the population. Also, medications needed to treat diabetes, including insulin, may increase the risk of car accidents (DCCT Research Group, 1987, also cited in Eby et al.)⁽²¹⁾ However, Veneman⁽⁷⁷⁾ conducted a review of the literature about this issue and concluded that the majority of the studies reveal that this risk is not so much different than that of non-diabetic people. Nevertheless, he states that crashes as a result of hypoglycemia happen and there has been an estimated 5.2 % the numbers of accidents for insulin-dependent patients. The literature review by Janke⁽⁴⁸⁾ cites research by Ward and Stewart (1990) that evaluated the relationship between hypoglycemia in Insulin-dependent patients and driving. They found that the majority of the subjects had experienced hypoglycemic episodes, and at least 30% considered these episodes to be a major concern. Coma or convulsions were present in 43% of the hypoglycemia episodes; 7% reported frequent episodes. Approximately 40% of the subjects suffered episodes while driving, and 13% of those involved in car crashes thought that it was a consequence of their hypoglycemia. Some other researchers^(44,78,42) mention diabetes disease among the illnesses that affect the abilities needed for safe driving. Carr⁽⁴⁴⁾ cited a 1994 study by Koepsell et al where diabetes was found to be the disease most predictive of motor vehicle crashes in older drivers. National Institute on Aging⁽⁴²⁾ recommends that diabetic patients who have problems controlling their blood glucose level should think about stopping driving.

Cox et al⁽⁷⁹⁾ conducted a study to analyze at which levels of blood glucose driving become impaired. Thirty-seven (37) adults (16 men and 21 women) with a mean age of 35.3 ± 7.1 years that had type I diabetes for at least two years, were taking insulin, were current drivers and were not taking another kind of medication that might affect driving performance or hypoglycemia, participated in the evaluation. A driving simulator (Atari Research Driving Simulator), which is a fixed platform and is considered to produce precise driving performance data in a realistic manner was used to assess driving. The results of this study show that driving performance was drastically affected by mild hypoglycemia in all different ranges (4.0-3.4, 3.3-2.8, < 2.8 mmol/l) and researchers indicated that when the blood glucose (BG) is in the range of 5.0-4.0, people should not drive without prophylactic treatment. Another finding of this study was that patients are not likely to take care of their level of blood glucose while driving even though they may be able to know when their driving was becoming impaired. In a previous study, Cox et al⁽⁸⁰⁾ evaluated driving decrement during and after hypoglycemia and how aware patients were of their driving decrements. They tested patients at euglycemia (mean blood glucose level 6.3± 0.89mM), mild hypoglycemia (mean blood glucose level 3.6± 0.33mM), and moderate hypoglycemia (mean blood glucose level 2.6± 0.28 mM) and at euglycemia again. Similar results were found and researches noted that “between 3.6 and 2.6 mM driving performance was disrupted and not reliably recognized by our patients.”(p.239)

Clarke et al⁽⁸¹⁾ studied how people with Type I diabetes made their decision to drive as part of their daily activities based on their perceived level of blood glucose and the real measured level. The participants were selected from four different academic medical centers; two different groups were selected two years apart. The 158 participants tested their blood glucose (BG) at least twice a day. Each of them had a handheld computer to keep a record of symptoms, cognitive function as well of the insulin dosage, food, activity, estimated and actual blood glucose levels and if they drove or not. Participants said they would drive 43% to 44% of the time when they thought that their blood glucose was 3.3 to 3.9 mmol/l, and 38% to 47% of the time when their real blood glucose was less than 2.2mmol/l. Around 50% of the participants said that they would drive at least 50% of the time knowing that their blood glucose was less than 3.9 mmol/l. Based on these results, the researchers suggest that physicians and caregivers should advise their patients about the consequences of driving with hypoglycemia and how necessary is to check their BG level before driving because persons with type I diabetes may not evaluate accurately when their BG level is too low to drive safely.

Dementia and Alzheimer’s Disease

Dementia is a syndrome characterized by loss of cognitive functioning to a level that significantly affects the performance of normal activities. Mental abilities, especially memory, decline as a consequence of dementia^(82,83) According to Daly⁽⁸²⁾ dementia is the most common neurological disorder affecting the elderly. Daily activities like planning meals, using a telephone, keeping a checkbook, driving a car and other self-care tasks are adversely affected by this disease. There are more than 100 conditions that can cause dementia, including strokes, drug interactions and malnutrition. The most common form of dementia is Alzheimer’s disease (AD).

Alzheimer’s disease is a progressive neurological disorder characterized by changes in behavior, personality, and the ability to perform normal activities.⁽⁸²⁾ The Mini-Mental State Examination (MMSE) is used to identify possible demented patients; it consists of a physical examination and various sensory and motor tests.^(84,85)

According to the Clinical Dementia Rating Scale (CDR), dementia can be divided into three stages: early, middle, and late.⁽²¹⁾ In the early stage, it is difficult to identify the disease and some patients are reluctant to accept the diagnosis. Symptoms of the middle stage include apathy, agitation, paranoia, sleep disorders, incontinence, aggressiveness, and severe depression according to Katzman (1987) and McKhan et al (1984) as cited in Eby et al.⁽²¹⁾ For patients in the late stage there is an almost total loss of functioning (Adler, Rotunda, Dunken, 1996, as cited in Eby⁽²¹⁾). The risk of getting Alzheimer ’s disease increases with age and one out of 15 people 65 years and over has this disease while one out of three people 85 years and over has this disease.⁽⁸³⁾ But according to Rayl,⁽⁸⁶⁾ one out of 10 people who are over 65 suffer from this disease. It is also estimated that half of the people whose relatives have AD will suffer from the disease by the age of 90 years old.⁽⁸²⁾ The Alzheimer’s Association reports that there are 4 million Americans with Alzheimer’s disease and 14 million people are expected to have this disease by 2050.⁽⁸⁷⁾ According to the Western and Central Washington State Chapter of the Alzheimer’s Association the symptoms of Alzheimer’s Disease (e.g. memory loss, disorientation, and changes in vision and perception) can affect the ability to drive.⁽⁸⁸⁾ On the other hand, the Alzheimer’s Association, Northern Virginia Chapter⁽⁸⁹⁾ points out that since “driving is a well-learned skill, a person with dementia still may appear to be driving well, even though the driving is really not safe.” The patients themselves do not know the danger to which they expose themselves and others. The increased risk per mile of having an accident is 19 times higher for a driver with AD than for other older adults without the disease according to a study reported in 1998 by the Annals of Neurology.⁽⁹⁰⁾ The same source also cited a 1996 study that compared driving records of 143 drivers with AD to 214 elderly drivers free of this disease and found no significant difference in traffic violation between these two groups. At the same time they noted that drivers with AD drove fewer total miles.

Carr et al⁽⁴⁴⁾ conducted a study for the Alzheimer’s Disease Research Center at Washington University in St. Louis, Missouri to determine the difference in crash rates and characteristics between drivers with dementia of the Alzheimer type (ADT) and drivers without dementia. The subjects consisted of 63 drivers with very mild and mild dementia of the Alzheimer type plus a control group of 58. The mean age of the subjects was 77 years. Traffic data were obtained from the state-recorded traffic crashes, and information from the participants was used to estimate the number of miles traveled per year. According to the researchers, it is possible that significant differences may exist, but none were found in this study. However, other researchers have found very significant differences between drivers with AD and other older drivers not suffering from AD.

Cox et al⁽⁹¹⁾ found that Alzheimer’s disease as well as dementia affect the characteristics of safe driving, for example, memory, visual attention, perception, and judgment. The Cox study evaluated the driving performance of 29 patients over 55 years old who met the criteria for probable Alzheimer’s disease (based on the Diagnostic and Statistical Manual of Mental Disorders, 3rd edition). The six month study used a control group of 55 years and older current drivers. Three instruments were used in this study, (1) a background and driving-history questionnaire, (2) the MMSE, and (3) the Atari Research Driving Simulator. The researchers noted that in comparison to the control group, patients with Alzheimer's disease were less likely to comprehend how to operate the simulator, drove off the road more often, spent more time driving considerably slower than the speed limit, spent less time driving faster than the speed limit, applied less brake pressure in stop zones, spent more time negotiating left turns and drove more poorly overall. These researchers cited a 1997 study conducted by Johansson et al that noted that 50% of autopsies of elderly drivers involved in fatal crashes show evidence of Alzheimer’s disease.

Ducheck et al⁽⁹²⁾ examined the relationship between visual attention measures and driving performance in healthy older adults and individuals with very mild dementia of the Alzheimer’s type (DAT). The participants were classified in three groups; healthy control, subjects with very mild DAT and subjects with mild DAT. All individuals had at least 10 years of driving experience and were actively driving at the time of the study. They used a series of tests, including a visual monitoring task, useful field of vision task, a two hour battery of psychometric tests, and a driving test. Researchers said that it was clear that demented drivers had lower driving scores and that the greater the severity, the lower the score. Additionally, their ability to pay attention “is affected by dementia severity and is predictive of on road driving performance” (p.P138).⁽⁹²⁾

Hunt et al⁽⁹³⁾ conducted a study to establish the effect of mild senile dementia of the Alzheimer type (SDAT) on driving. Twelve (12) patients with very mild dementia, 13 with mild dementia and 13 persons without dementia (control group) participated. The presence of dementia and its severity was evaluated by experienced clinicians. The ability to follow the driving instructor’s directions, appropriate decision making in traffic, and correct interpretation of traffic signs were taken into account along with overall driving performance. People with very mild SDAT and the control group were evaluated as safe drivers but 40% of the mild SDAT group had driving impairment and were not able to pass the road test. The researchers concluded that some SDAT patients have safe driving skills but the likelihood of poor driving increases as the severity of the disease increases.

These findings were similar to those found by Ott et al⁽⁹⁴⁾ who used patients of the Roger Williams Medical Center’s AD and Memory Disorders Unit, excluding those who had never driven. All the subjects used in this study had had Single-Photon Emission Computed Tomography (SPECT) imaging done as part of the evaluation for suspected AD or any type of degenerative dementia. The researchers were able to find a correlation between the severity of driving impairment and the severity of dementia as measured by Clinical Dementia Rating (CDR) and Instrumental Activities of Daily Living (IADL), but not necessarily by global cognitive function as it was measured by The Mini-Mental State Examination (MMSE). Through this study, researchers were able to demonstrate the existence of a relationship between driving impairment and visual perceptual dysfunction. The study states that the severity of driving impairment in patients with AD has a relation to changes in regional cortical functions. Researchers concluded that “the contribution of such regional changes to driving impairment should be considered in future investigations of driving and dementia and in the development of screening examinations for driving impairment among this population” (p.159).

Dubinsky et al⁽⁹⁵⁾ addressed the issue of driving and Alzheimer’s Disease to see how extensive the traffic safety problem was. Based on previous studies related to this problem, they concluded that “The relative risk of crashes for drivers with mild AD is greater than our society tolerates for any group of drivers” (p. 2209). They considered that the risk imposed to society and themselves by drivers suffering from AD is very similar to that of youngsters aged 16 to 19, but in the case of youngsters, they are expected to perform better as the approach adulthood contrary to the AD drivers, who are expected to get worse over time. They reported that in all the studies which evaluated AD drivers, they functioned worse than the control groups. They concluded that there is no doubt that AD patients have a higher accident rate than those not afflicted with AD. Researchers suggest that patients with very mild and mild AD disease should be told not to drive. They said that the first performance test of drivers with mild dementia was reported by Fitten and others in 1995; drivers with mild dementia were compared to drivers with diabetic retinopathy, multi-infarct dementia and healthy older adults. The researchers administered an on-the-road test on a 2.7 fixed mile road at a Veteran’s Administration Medical Center. The results show that the performance of drivers with mild dementia was much lower than that of the control group and the retinopathy group.

Logsdon et al⁽⁸⁴⁾ examined the driving status of AD patients to identify those who were no longer safe drivers. Patients were divided into three (3) groups; group one consisted of 22 subjects still driving without difficulty, the second group had 23 subjects still driving but having difficulty, and the third group had 55 subjects who had already stopped driving because of cognitive impairment. Researchers pointed out that many patients with AD keep driving regardless of their cognitive impairment. The difference between the first two groups was minimal, but those who had stopped were more impaired than the first two groups. “This investigation points to the need for an assessment of driving safety as part of a thorough clinical evaluation of dementia” (p. 587).

Fox et al⁽⁹⁶⁾ evaluated 19 drivers in Australia with mild dementia, using a standardized open road evaluation and expert judgment. All patients participated in an on-the-road assessment conducted in a vehicle with automatic transmission, power steering, dual brakes and an engine cut off switch. A standardized route in traffic was used to analyze driving performance in daylight and in light to moderate traffic. Based on the driving assessment, 12 subjects were considered unsafe drivers and seven (7) of the patients passed; however, six months later, four out of the seven patients failed the same on-road evaluation test. Based on this finding, researchers suggest that drivers with AD should be periodically evaluated for driving performance.

The American Academy of Neurology has issued guidelines on driving and patients with Alzheimer’s disease. Dr. Richard Dubinsky, lead author of these guidelines states that Alzheimer’s patients with a mild severity level have a considerably high accident risk and should not drive while patients with a very mild severity level may still drive but should be monitored and evaluated every six months. Dr. John C. Morris holds a similar opinion; he finds the guidelines reaso

DISCLAIMER STATEMENT

Acknowledgements: