The incidence of high vehicles striking low bridges has increased considerably since about 1970. Now, between 400-500 such accidentsoccur every year. This study investigated two possible reasons for the accidents. These were drivers' knowledge of their vehicle heights, and drivers' understanding of the low bridge warning signs. Drivers' opinions of ways of preventing the accidents were also obtained.only 12% of drivers were correct in their estimate of their vehicleheight and 27% were within 3 in (76 mm) of the correct height. The majority of drivers made estimates which erred on the 'safe' side. 21% of drivers did not understand the road sign that shows 'headroom at hazard ahead'. The ways of preventing high vehicles striking low bridges most popular with the drivers were those which provided themwith information which was most directly relevant, i.e, whether or not the vehicle would get safely under the bridge.(A)
Abstract