Assisting the older driver - SWOV

Assisting the older driver
functional age were not established for workload. However, functional age
did affect workload in general. In most cases, functionally old participants
had higher workloads than functionally young participants (see e.g., Ponds,
Brouwer & Van Wolffelaar, 1988, and McDowd & Craik, 1988 for similar
results). This seems to be the mere result of having to carry out two tasks
simultaneously. The reaction times of drivers of different functional age
groups were the same when they had to carry out a detection task while they
were sitting in a parked simulator car. However, when performing the same
task while driving, functionally old drivers had longer reaction times than
both functionally young and middle‐aged drivers. A related study showed
that as traffic situations got more difficult, the workload of all drivers
increased further. However, this increase in workload did not increase with
functional age. An interaction effect was only established for the increased
effort needed to combine the primary and secondary task (Davidse, Van
Wolffelaar, Hagenzieker & Brouwer, 2007; see Chapter 6).
Driver support also affected general driving behaviour. Messages regarding
an obstructed view of the intersection and messages which reminded
participants that they had to yield to traffic from the right led to lower
driving speeds on the corresponding intersections. Messages regarding safe
gaps that were sent to participants who, while driving on a major road,
turned left in front of oncoming vehicles, led to higher speeds while passing
the intersections.
For some messages, the actual delivery of the message was dependent on the
behaviour of the participant. Messages regarding the approach of a major
road or an obstructed view of the intersection, for example, were only sent if
the participant drove at a speed that was higher than 30 km/h, assuming the
driver had already adjusted behaviour to the local circumstances if he was
driving slower. As a result, the average number of messages received by
participants could vary. Surprisingly, functionally old participants received
the fewest messages regarding safe gaps, the approach of a major road, and
changed speed limits. A possible explanation for the first type of messages
may be that older drivers stopped further away from the intersection to look
for safe gaps in the traffic stream. A related study that examined other data
of this same experiment showed that functionally old participants generally
stopped two meters further away from the intersection to decide whether it
was safe to join traffic after turning left or right than both young and middleaged
participants did (13.8 m versus 11.7 m and 11.8 m respectively; see
Davidse, Van Wolffelaar, Hagenzieker & Brouwer, 2007 or Chapter 6). As
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