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 Older
Drivers in Crashes: The Mistakes They Make at
Intersections Differ From Younger Drivers
ARLINGTON, Va., March 19 /PRNewswire-USNewswire/
-- Studies going back decades reveal that older drivers are
over-represented in collisions at intersections. Forty percent of
the fatal collisions of people 70 and older, compared with 23
percent of the crashes of 35-54 year-olds, occur at intersections
and involve other vehicles.
What mistakes are leading older motorists to
get into intersection crashes?
A new Insurance Institute for Highway Safety
study focuses on intersection crashes involving more than 200
drivers in 3 age groups -- 2 groups of older drivers (70-79 years
old and 80- plus) and a comparison group of 35-54 year-olds.
The researchers studied crashes
involving injuries on Connecticut roads during
2003-04, examining police reports and photographs of
the intersections where the crashes occurred. The
researchers also interviewed the drivers found at
fault in the collisions.
"The interviews with the at-fault drivers are
what set this study apart from earlier ones, giving a clearer
picture of the mistakes people of various ages are making behind the
wheel and why," says Anne McCartt, Institute senior vice president
for research. "Previous studies have compared the kinds of crashes
older versus younger drivers get into, and in the interviews we
delved further into the underlying reasons."
Older drivers fail to yield: The types of
crashes in which drivers 70- plus years old are at fault differ from
crashes for which 35-54 year-olds are responsible. These differences
amplify with age so that the crashes of drivers 80 and older also
differ from those of 70-79 year-olds.
Among the drivers in Connecticut, rear-end
crashes accounted for a lower proportion of 80-plus drivers'
intersection crashes. Both groups of older drivers, those 70-79 and
80-plus, had lower proportions of run-off-the-road crashes than
35-54 year-olds.
In contrast, failure to yield the right of way
to other vehicles led to more than half of the intersection crashes
for which the oldest drivers were responsible. This compares with
about one-third of the intersection crashes of 70-79 year-olds and
about one-fourth of those involving 35-54 year-olds.
Why they crashed: Reasons for the intersection
crashes varied by driver age. People 70-79 made more evaluation
errors than drivers of other ages.
That is, they saw potentially conflicting
vehicles but misjudged whether there was time to proceed. Drivers in
the other age groups (35-54 and 80-plus) more often failed to see
potentially conflicting vehicles. The 35-54 year-olds said it was
because they became distracted, while most of the drivers 80-plus
said they were looking but simply didn't see the conflict.
McCartt says the failure to see other vehicles
"may be due to increases in vision impairments, which escalate
rapidly after about age 75. Another factor could involve the
complexity of urban intersections, with vehicles traveling in
multiple directions. Older drivers may experience decreasing ability
to process the multiple sources of information at once and maneuver
safely."
Range of head movement might also be a factor
in older drivers' crashes. These ranges have been found to decrease
with age, which could hinder a driver's ability to see potentially
conflicting vehicles.
Whatever the reasons for the intersection
crashes, those involving failure to yield occurred more often where
traffic is controlled by stop signs than at intersections with
signal lights (more rear-end crashes occurred at the signals).
Fifty-nine percent of the failure-to-yield crashes occurred at stop
signs, and 50 percent of these crashes occurred while motorists were
turning left. The proportions didn't vary much across the 3 age
groups.
Other studies do indicate an age effect. For
example, a 2002 study by University of Kentucky researchers found
that each advancing year of age after 65 increases by 8 percent the
odds of getting into a crash that involves turning left. Not
surprisingly, it's the converse in Australia.
Motorists there travel on the left side of the
road, and as Australian drivers get older they become
over-represented in collisions involving right turns.
Some ideas that might help: Older people
represent an increasing proportion of the US population, and this
trend is escalating as baby boomers age. Older people are keeping
their driver's licenses longer than in past years, and they're
driving more miles.
For these reasons, it's becoming increasingly
important to find ways to reduce the frequency and severity of older
people's crashes, including the collisions that occur at
intersections.
One way would be to add green arrows to protect
left turns at intersections controlled by signal lights (see Status
Report, Sept. 8, 2001; on the web at
http://www.iihs.org/). Then
motorists, including older people, wouldn't have to judge how fast
vehicles are approaching from the other direction and whether
there's enough time to turn in front of them.
Another approach would be to construct more
roundabouts in place of intersections with traffic lights and stop
signs. These circular intersections have design features that slow
traffic and promote efficient flow (see Status Report, May 13, 2000;
on the web at
http://www.iihs.org/).
They also might be easier for older drivers to
navigate because vehicles go through them in one direction, not from
multiple directions.
For a copy of "Crash and error types of older
drivers' intersection crashes" by K.A. Braitman et al., write:
Publications, Insurance Institute for Highway Safety, 1005 N. Glebe
Rd., Arlington, VA 22201, or see
http://www.iihs.org/.
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