Visual Performance for Motorists - Road Lighting: Fundamentals, Technology and Application - page 44

Fig. 3.32 Driving simulator
used by Muzet ( 2003 )
allowing EEGs to be recorded
during simulated (night)
drives. Photograph CI2N

to road lighting and optic flow. Effects of, for example, the influence of lighting
level and spectrum of light source on the basic mechanism of motion perception are
therefore not known, but could be important.

3.10 Lighting, Brain Activity and Alertness

There exists a negative relationship between driver fatigue and road safety. Both the
performance and vigilance, or alertness, of the fatigued motorist decrease. Sleepiness
or drowsiness may lead to micro sleeps of from less than a second to some tens of
seconds. The risk of this occurring is especially great during long, monotonous
night drives. A test, carried out by the university of Paris, with night-time motorists
equipped with instrumentation to measure their EEG so as to determine the duration
of each individual micro sleep whilst driving, has shown alarming results (Mollard
2003 ). On a 415 km stretch of unlit motorway, those night drivers that did not take
a rest before the beginning of their night drive showed a cumulative micro-sleep
time of 6 min and 12 s. No extensive tests have yet been carried out on equally-
long stretches of lighted motorways. Tests in a simulator in which EEGs have been
recorded (Fig. 3.32 ) have shown that the sleepiness during the first hour of a nighttime
motorway drive is less on a lighted road than on an unlighted road (Muzet 2003 ;
Remande 2009 ). During the subsequent three driving hours of the test there is no
difference in sleepiness on the lighted and unlighted road. The same study showed
that after a 1-h drive in the middle of the night on an unlit motorway, the resulting
sleepiness decreases rapidly (on a 5-point sleepiness scale from 4.5 to 3.1) while
subsequently driving on a lighted stretch of motorway. The lower level of sleepiness
was measured during the whole 10 km drive on the lighted stretch. Sleepiness started
rising again after a subsequent unlighted stretch.
It seems that neurophysiologic studies indeed can help to identify which road
conditions, result in the greatest risk of sleepiness and drowsiness (Brown et al.
2013 ). Such studies aimed at lighting conditions could possibly lead to specific
lighting scenarios for long motorways.