The authors conducted six tasks with younger (ages 21-35), middle-aged (ages 50-64), and older (ages 65 and up) drivers and pedestrians. Task 1 evaluated effective word order for message signs, showing that decision making efficiency for standard orders for Dynamic Message Signs (DMS) and Portable Changeable Message Signs (PCMS) did not differ significantly from experimental orders, though some trends favored experimental orders. Task 2 assessed the role of headlight beam setting on sign perception, showing that fluorescent sheeting was only superior to standard sheeting under low beam conditions. Task 3 assessed the efficacy of supplemental pedestal traffic signals, showing no advantage in driver stopping behavior for pedestal-active conditions. Task 4 evaluated the effectiveness of internally illuminated overhead street signs using standard sheeting compared to highly reflective sheeting. Legibility distance was improved for standard sheeting (vs. reflective) only in middle-aged drivers and marginally for older drivers. Task 5 evaluated the effectiveness of pedestrian crossing buttons using different forms of feedback. An observational study showed a trend (not statistically significant) for an advantage in compliance with traffic signals when enhanced feedback buttons were used at Tallahassee intersections compared to no-feedback buttons. An experimental field study showed better confidence that a button was pressed with enhanced feedback only in middle-aged and older pedestrians. Compliance was related to intersection characteristics - higher for high traffic and longer intersections - and was greatest for middle-aged pedestrians. Task 6 assessed the efficacy of character size for two dynamic message signs, one with 16.8” and one with 18” characters, finding that legibility was greater for the 16.8” character display, though it had 3 times brighter pixels. (Author/publisher)
Abstract