Aging Driver and Pedestrian Safety Lab

In Task 1, we analyzed pedestrian crash data for parking lots in West Central Florida, finding: 1) Seasonal variation in crash frequency in parking lots with higher frequencies in winter and spring, likely associated with tourist influxes to Florida; 2) Variation in crash frequency during daytime hours with peaks from noon to 6 pm; 3) Greater crash risk (per 1000 population) for all crashes and serious crashes for younger (age 15-19) and older (age 75+) pedestrians, as well as for younger (age 20-24) and older (age 65+) drivers; 4) Greater crash frequencies in smaller than larger parking lots and in residential parking lots; 5) No significant variation in crash frequency by parking space angle or by presence of crosswalks; and 6) Greater frequency of back out crashes for older pedestrians (age 75+) and forward driving crashes for younger (age 14 and below) pedestrians.

In Task 2, an observational study of pedestrian behavior in parking lots, we found: 1) Greater use of crosswalks by all age groups (young, middle, old) in larger parking lots, though no significant age variation occurred in using crosswalks; 2) No significant age variation was seen in lateral distance to parked cars when pedestrians were navigating; and 3) Greater distracted walking by younger than older pedestrians.

In Task 3, a field experiment requiring middle-aged and older pedestrians to navigate through an open parking lot and a parking garage wearing eye-tracking equipment, we found: 1) Age differences in walking speeds when navigating parking lots with older pedestrians, aged 65 and older, walking about 0.6 feet/s slower than middle-aged adults, aged 50 to 64; and 2) No significant age differences in attention patterns when navigating parking lots, as indicated by scanning behavior (e.g., head turns, eye fixation patterns) or in response to a backing out threat (fixation response time, walking path deviation).

We conclude that the most likely reason for the differential crash types in parking lots for older compared to younger pedestrians probably lies in the reduced speed with which older pedestrians can react to hazardous events. Potential countermeasures to improve safety could include age-targeted educational campaigns and development and deployment of collision-avoidance technology. We also recommend that future work focus on developing new ways to assess pedestrian crash exposure in parking lots that take into account walking speed and distance from parking spaces to store fronts.

We 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.

Eight studies were conducted using lab and field experiments (day and night) to assess sign perception and pedestrian awareness for younger, middle-aged, and older drivers, and to assess older and younger pedestrian intersection crossing behavior.

Study 1 showed that fluorescent yellow sign sheeting marginally enhanced perception and comprehension distance over standard sheeting. Age strongly predicted sign perception response time and perception distance. Lab-based measures predicted field performance well.

Study 2 showed superiority of uppercase street sign names over mixed case, particularly for longer names and for older drivers. Lab to field prediction was weak.

Study 3 showed an advantage for symbol over word warning signs, and weak prediction from lab to field performance.

Study 4 showed that older drivers comprehended portable changeable sign messages at about 870 feet, below the MUTCD guideline of 0.5 miles visibility.

Study 5 used film clips with animated countdown signals and novel pie signals. Older pedestrians did not differ from younger ones for crossing decisions, though exhibited less comfort. Pie displays promoted lower likelihoods for decisions to cross long intersections compared to short and intermediate ones; the opposite occurred for countdown displays.

Study 6 showed adequate legibility (300 feet) for countdown displays in the field. Older pedestrians crossed less often and were more likely to fail to cross in time than younger ones.

Study 7 showed that all drivers were sensitive to the presence of a pedestrian during left and right turns, indicated by vehicle velocity profiles, though older drivers drove more slowly.

Study 8 showed much reduced sign perception distances with simulated rain conditions on the vehicle windshield, though no age differences in performance, and an advantage for symbol over word warning signs.