The legibility of the Clearview alphabet on freeway guide signs constructed with microprismatic retroreflective sheeting was studied. The Clearview legibility results were compared to the legibility of freeway guide signs constructed with the Series E (Modified) alphabet. A total of 60 subjects divided into three age groups participated in this nighttime study. The findings indicate that the Clearview alphabet provides statistically longer legibility distances than the Series E (Modified) alphabet. The largest 50th-percentile differences were 58 ft for shoulder-mounted signs and 54 ft for overhead signs. Depending on speed, these improvements can provide a driver with up to 0.7 s more time to read freeway guide signs. In terms of subject age, the largest benefits of Clearview were associated with older drivers.
Samenvatting