Abstract
The problem was to determine if there is a significantly higher number of accidents in expressway are as which have illuminated and alternating advertising signs than in areas which do not have these signs. Previous research has conflicting evidence, but it is assumed that highly illuminated advertising signs in congested and expressway areas produce driver distraction and contribute to accidents. Statistical analysis of the accident data from the Chicago Expressway System did not fully confirm this theory. In two cases illuminated and alternating advertising areas did not have higher accident rates than other non-advertised areas. However one sign area did have significantly higher accident rates.