THE PERCEPTION OF VEHICLE SPEEDS BY PEDESTRIANS

Experiments into pedestrian perception of vehicle speeds were carried out on a busy street in central London, England and on a section of a four-lane thoroughfare with free-flowing traffic subject to a 40 mph speed limit. Seven volunteer subjects, grouped on the pavement, were asked to record estimates of a certain vehicle speed as it passed a reference point. Observations of 50 vehicles were made at each site. Then the subjects were moved and 50 more observations were made at a different angle to the reference point. The average speed of the vehicles observed was 32 mph and the average of the estimated speeds was 31 mph. The average errors of the seven individuals ranged from 02 mph to -6 mph. The standard deviation of estimated minus true speed was about 5 mph for all subjects and there was a tendency for observers to underestimate high speeds. /Author/