Motor Vehicle Crashes in Older Drivers Thomas Songer, PhD University of Pittsburgh

Learning Objectives Understand the current evidence regarding crash risks in older drivers Identify the two concerns that licensing authorities seek to balance in older drivers Introduce the study of medical conditions as causal agents in crashes

“Texas police say a 92-year- old driver took a wrong turn on her way to exchange a pair of shoes and ended up on the tarmac of Houston Gulf Airport, where she crashed into a Piper plane taxiing toward the runway. No one was seriously hurt.”

What is the crash risk related to older drivers? How important is this risk?

Number of Licensed Drivers Age millions of drivers NHTSA, FHWA

Crash Involvement Rate Age per 1000 licensed drivers NHTSA, FHWA

Total Miles of Travel Age millions of miles NHTSA,FHWA

Involvement Rate by Mileage Age per 100 million miles VMT NHTSA, FHWA

Fatality Rate Age per 100 million miles NHTSA, FHWA

Injuries and Fragility UP Age Rate per 100,000 per year Injury Rate Mortality Rate

Fatal Accidents of Older Drivers

Violations in Fatal Accidents by Age

Growth of the Elderly Population Year number (millions) yrs yrs 85+ yrs

Car Trouble Older Drivers Pose Growing Risk on Roads as their Numbers Rise They Crash More Than Many, Yet Taking Away Wheels Leads to Isolation, Anger Wall Street Journal, October 29, 1993

With no standard method to pinpoint dangerous elderly drivers and get them off the roads, perhaps the best that many states can do is to simply encourage people to anonymously report bad drivers. Yet many people are loathe to do so. One such person says she still feels guilty about a woman she turned in a few years ago. Slide 1 0f 3

The woman, who was in her early 80s, drove poorly and often left her car parked halfway in the street. Her neighbor pointed out the problem, but the woman always said she was too tired to park again. Worried that the woman might kill someone, the neighbor called the police. Slide 2 of 3

Soon after, state officials retested the woman and revoked her license. Without her wheels, the woman was forced to move into a nursing home, where she subsequently died. “She was crushed” over losing her license,” The neighbor recalls, “I did feel responsible.” Slide 3 of 3

Relation between Social Activities and Driving Habits in Women Transportation Mode 56.7*63.6*80.9 % club members *99.0 % who leave house weekly *61.1 % >3 close friends 64.3*85.3*78.5 % seeing children Other ModeOthers DriveDrives Self Social Activity Huntley et al. 1986

"Officials Try to Balance Public Safety Against the Rights of Older Drivers" Crash Risk Social Opportunities New York Times, May 4, 1992

Licensing Older Drivers in the USA No age provisionsMore frequent license renewals Require testing (road or vision) Source: IIHS (June 2001)

Issues for Appropriate Licensing Does licensing reduce crash involvement? Can high risk drivers be identified by licensing agencies? Are screening tests feasible? What is an acceptable risk for crashes? How many drivers would be affected? What are the social costs to the driver of being denied a license?

“legislatures and public agencies are frequently under pressure to restrict drivers with medical characteristics presumed to be a hazard to driving” Haddon, Baker 1981

Relative risk of motor vehicle collision injury by selected cardiovascular conditions Odds Ratio % prevalence in Cases Controls (95% CI) Coronary heart disease Myocardial infarction ( ) Angina pectoris ( ) Coronary-artery bypass ( ) Any of above conditions ( ) Koepsell 1994

Relative risk of motor vehicle collision injury by selected neurological conditions Cerebrovascular disease Stroke ( ) Transient Ischemia ( ) Either of above ( ) Dementia ( ) Head Injury ( ) Koepsell 1994 Odds Ratio % prevalence in Cases Controls (95% CI)

Relative risk of motor vehicle collision injury by selected medical conditions Condition Fall in previous year ( ) Alcohol abuse ( ) COPD ( ) Osteoarthritis ( ) Rheumatoid arthritis ( ) Cancer ( ) Diabetes mellitus ( ) Koepsell 1994 Odds Ratio % prevalence in Cases Controls (95% CI)

Research Issues Which population Exposures Definition of Crashes Recall bias Reporting bias

Reasons for Stopping Drivng in the Elderly Advancing Age Increasing Number of Factors from above Medical Impairment Activity Limitation Marottoli, 1993 Low Income

Prevalence of Driving Cessation by Age > 85 Age Prevalence %

Future Research - National Agenda Establish Crash Risk for Medical Conditions Document consequences of driving cessation Improve vehicle crashworthiness for elderly Identify causes of crashes at intersections Examine physician role in licensing Examine voluntary reporting of drivers Examine how older drivers compensate for limitations