Aging Drivers: Intersections Are Danger Zones

It's intuitive as well as true: The toughest spots for senior drivers are intersections. That's where most accidents involving elderly drivers occur, and where the most serious car crashes take place. Forty percent of the fatal collisions for people 70 and older occur at intersections and involve other vehicles, compared with just 23 percent of such crashes for 35-to-54-year-olds.

So intersections — and how and whether they can be modified in the interests of elderly drivers — are attracting increasing attention from researchers, advocacy groups and government agencies.

The challenges posed by crossroads also apparently are getting more attention from senior drivers: Fatal crashes at intersections declined dramatically in a new study by the Insurance Institute for Highway Safety that showed a 21-percent decline in crash deaths among drivers 70 and older in the decade ended in 2006.

The Problem With Left Turns

The most extensive and recent research on traffic intersections has shown that senior drivers flirt with many sources of danger near, at or within intersections. One of them is a higher tendency to run into cars in front of them. But by far, the inability to safely execute an unprotected left-hand turn — one without a left-turn signal — is their stiffest challenge.

To be sure, left turns are dangerous for everyone. So at thousands of major intersections across the country, they're protected by a green arrow. Some places try other approaches. In Michigan, for example, the locally infamous "Michigan left-hand turn" requires a driver who wants to turn left to first make a right turn, then make a legal U-turn in the median strip.

Unprotected left turns present one of the most hazardous scenarios in routine traffic. "It's a relatively complicated situation for any driver, because you're processing multiple sources of information and having to make multiple decisions, such as judging the speed of the oncoming vehicle or vehicles, how quickly you can react and so on," said Anne McCartt, senior vice president for research at the Insurance Institute for Highway Safety (IIHS).

But because of the specific challenges older drivers face and the particularly complex dynamics of traffic movements through an intersection, elderly drivers are especially bad at navigating unprotected left turns. Each advancing year of age after 65 increases by 8 percent the odds of getting into a crash that involves turning left, according to a 2002 study by University of Kentucky researchers.

"Older drivers aren't speeders or DUI," said Elinor Ginzler, director for livable communities for the AARP. "But they have more problems with left-hand turns. And the way that most left-hand turns are designed, it accentuates the problematic ability of the older driver to do that."

Failure to yield the right of way to other vehicles led to more than half of the intersection crashes for which drivers 80 or older were responsible, according to a newly released IIHS study of Connecticut intersection crashes in 2003 and '04. This compared with about one-third of the intersection crashes even for 70-to-79-year-olds and about a quarter of those involving 35-to-54-year-olds.

Stop signs are more of a culprit than traffic signals. Fifty-nine percent of failure-to-yield crashes occurred at stop signs in the Connecticut study, and 50 percent of those crashes occurred while motorists were turning left — for all age groups.

The physiological and mental ravages of aging appear to be largely responsible for older motorists' exaggerated problems at intersections. Vision deterioration impairs elderly drivers' ability to see other vehicles that may be relevant to them in all directions, even behind them. Cognitive challenges mean they often can't make decisions fast enough, especially about whether and when to make a left turn ahead of vehicles that may be approaching from the right. And declining physical dexterity impedes their ability to execute decisions.

"Often they can't judge the time until there would be contact with an approaching vehicle, and their decision about what a safe gap is means that seniors delay longer and longer before entering traffic and feel more and more anxiety until they do," said Richard Backs, a psychology professor and expert on driving vision at Central Michigan University. "But it doesn't make them safer because at some point they still have to execute the turn."

Making Intersections Less Dangerous

Road designers and senior-driving experts agree that, when it comes to intersections per se, two main types of improvements would help significantly. One of them is making protected left-hand turns ubiquitous, wherever possible, at intersections governed by traffic signals. That way, older motorists don't have to make the most problematic decisions about when to proceed.

A second popular suggestion is to build more traffic circles, or roundabouts. They are common in Europe but not so numerous in the United States, although more are being constructed all the time. Research by the IIHS identified three major advantages of roundabouts that combine to dramatically reduce the potential for serious car crashes, compared with conventional intersections. Each of these pluses of roundabouts is particularly helpful to older drivers.

The first safety edge is that all drivers are proceeding in the same direction. The second: Everyone is traveling at very low speeds. The third advantage is that traffic circles eliminate head-on and right-angle crashes that tend to be the most destructive.

"We recognize that, when they're first constructed, traffic circles can be confusing for all ages because they're still so rare in this country," said McCartt of the IIHS. Moreover, roundabouts aren't without their own dangers, "because you don't have the security that you may feel at an intersection where there is a stop sign or a stop light and then you go."

But over time, McCartt said, "Drivers are much more in favor" of traffic circles as they get used to them.

Another useful approach is to remind senior drivers that a certain amount of caution, as in all driving, can be a good thing at intersections. For example, in an AARP driving-improvement class they teach in Michigan, Jack and Nancy Stegeman stress that the law emphasizes "yielding" to other motorists rather than asserting "right of way."

"It's just safer to think that way," Jack Stegeman said.

Below are links to all of the installments in this series.

What Should We Do About Grandma's Driving?
Aging Drivers: Intersections Are Danger Zones
How To Improve Seniors' Driving Skills
Better Cars, Equipment Assist Senior Drivers
When It's Time To Hang Up the Keys
Florida Paves the Way for Senior Drivers

Dale Buss is a journalist and author based near Detroit.