Assisting the older driver - SWOV

Effects of intersection design on workload and driving performance
These three scores were first converted into normal scores (z‐scores) and then
averaged (after making sure that scores on all tests were scaled in the same
order, high scores indicating better performances than low scores). After
having ranked participants according to their average score, participants that
were in the lowest quartile (having the lowest average scores) were assigned
to the oldest functional age group, and participants in the highest quartile
(highest averages) were assigned to the youngest functional age group.
Remaining participants (50% of all participants) were assigned to the “inbetween”‐group
that we called ‘functionally middle‐aged’.
Functional age
Young Middle Old
Total
Young (30‐50) 27 42 2 71 a
Old (70+) 1 8 24 33
Total 28 50 26 104
a
One chronologically young person did not complete the cognitive tests and
could therefore not be assigned to one of the functional age groups.
Table 6.1. Comparison of chronological and functional age groups (number of
participants).
6.2.2. Procedure
All participants who had shown interest in participating in the study by
ringing us or sending an e‐mail were called back to test them on sensitivity to
simulator sickness and to check their driving experience. Those who
appeared not to be sensitive to simulator sickness as indicated by never or
seldom being sick while travelling by plane, train, boat or as a passenger at
the back seat of a car (see Hoffman, Molino & Inman, 2003), and who had
more than five years of driving experience were invited to participate in this
study. Those willing to participate were informed about the experimental
procedure and received some extra information by mail, as well as an
informed consent form, a questionnaire on driving behaviour and
information on how to find the driving simulator that was located in the
University Medical Centre in Groningen (UMCG).
Participants were invited twice to the UMCG. During their first visit, they
returned the completed questionnaire and their signed informed consent
form, they were administered the three tests on cognitive functioning (see
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