Assisting the older driver - SWOV

Intersection design and the older driver
5.2. A pilot study on the relationship between
characteristics of intersections and crashes involving
older drivers
5.2.1. Introduction
Older adult drivers (i.e., those aged 75 and above) distinguish themselves
from the average road user by a higher physical vulnerability and a
somewhat higher crash involvement. Because of these two factors, older
adult drivers have a higher fatality rate. This fatality rate can be reduced by
taking secondary safety measures (i.e., improve the crashworthiness of
vehicles, promote the use of safety devices) and by taking measures that are
specifically aimed at preventing those types of crashes that are
overrepresented in the total number of crashes involving older drivers
(Brouwer & Davidse, 2002; Maycock, 1997). The present study focuses on the
latter opportunity to lower the fatality rate of older drivers.
The somewhat higher crash involvement of older adult drivers concerns a
number of specific crash types, of which crashes at intersections, crashes
while turning left and crashes as a result of failing to yield are the most
important ones. Note that these three descriptions can actually describe the
same crash. In short, research has shown that the crash type that is
overrepresented among older drivers is one in which the older driver is
turning left at an intersection and fails to yield (Aizenberg & McKenzie, 1997;
Davidse, 2000; Hakamies‐Blomqvist, 1993, 1994c; McGwin & Brown, 1999;
Zhang et al., 1998). Therefore, to reduce the fatality rate of older drivers,
focus should be on preventing crashes that occur while turning left and on
preventing crashes as a result of failing to yield. According to Fuller’s taskcapability
interface model (Fuller, 2000, 2001, 2005), crashes are likely to
occur if task demands are higher than the capabilities of the driver (see
Section 4.2.1). To prevent crashes from happening, demands and capabilities
should be tuned to one another. Taking the demands of the road
environment as a starting point, the aim of this study was to examine
whether it would be possible to identify characteristics of intersections that
coincide with a higher frequency of crashes involving older drivers. If that
were the case, changing these characteristics would lower task demands.
Assuming that the capabilities of the driver do not deteriorate any further,
these lower task demands will ease the task of passing the intersection in
question, resulting in a reduction of the number of crashes at intersections.
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