Assisting the older driver - SWOV

Assisting the older driver
with overhead lighting they state that a minimum in‐service contrast level of
2.0 is sufficient.
In addition to the provision of a painted edgeline on the road surface, Staplin
et al. (2001) recommend that all curbs at intersections (including median
islands and other raised canalization) be delineated on their vertical face and
at least a portion of the top surface. Vertical surfaces should be introduced by
cross‐hatched pavement markings.
5.3.4. Traffic signals and fixed lighting
As far as traffic signals and fixed lighting are concerned, the older drivers’
need for increased levels of luminance and contrast should be weighed
against their sensitivity to glare.
Traffic signals
Since background plates provide more contrast between the traffic light and
its direct surroundings without increasing the risk of blinding, they
compromise between lighting, contrast and glare and are a good alternative
to increased intensity of light. Current Dutch guidelines indicate that
background plates should only be omitted when the available space is such
that the plate would be too close to the carriageway (CROW, 1998a, p. 753;
s.n., 1997, Article 1.11). Glare can be further reduced by reducing the
intensity of traffics signals during darkness, except when this is unnecessary
or undesirable because of the (fixed) lighting of the surroundings (s.n., 1997).
Fixed lighting
Lighting is more important to older adults than to the average road user.
Both the reduced pupil size and yellowing of the lens of the older adult
reduce the amount of light reaching the retina. A consequence of this
reduced retinal illumination is that sources must be of higher intensity to be
seen at night (e.g., Olson, 1993). Furthermore, timely warnings of unexpected
situations and changes in lane configuration and lane width are helpful to
older adults because of their increased perception‐reaction time and these
warnings can be provided for by lighting these areas. Therefore, Staplin et al.
(2001) recommend fixed lighting installations (a) where the potential for
wrong‐way movements is indicated through crash experience or engineering
judgement; (b) where twilight or night‐time pedestrian volumes are high;
and (c) where shifting lane alignment, turn‐only lane assignment, or a
pavement‐width transition forces a path‐following adjustment at or near the
intersection.
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