Farther and safer: An illusion engendered by incapability?

Previous studies have observed that pedestrians tend to select gaps of farther distances between vehicles when crossing roads; however, the causes were unclear. Such gaps may create dangerous illusions because a farther distance for a given pedestrian crossing time implies that a vehicle is actually traveling faster. This study aimed to identify the causes of this farther-and-safer illusion, especially concerning elderly pedestrians. In particular, we examined behavioral changes after the burden of estimating the time to arrival (TTA) of an approaching vehicle has been removed through the provision of a countdown. Repeated measures collected for 82 subjects were examined using multilevel generalized linear models. The analysis results indicated that on average, the countdown effectively enhanced gap selection safety in both young (20-45 years) and elderly (60 years and older) subjects; however, its effect on reducing the illusion was heterogeneous between and within subjects. Most elderly subjects were sufferers of the farther-and-safer illusion even when their TTA estimation burden had been removed, implying that a decline in physical ability is not the primary cause of the illusion. Although the gap selection behaviors of young subjects were relatively modifiable, the behavioral changes sometimes led to a worse consequence, suggesting an incapability of properly using the countdown information. This study suggests that simply telling elderly pedestrians to recognize their age-related function changes is insufficient for improving their safety; other countermeasures are also required.