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Abstract
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Introduction
Pedestrian countdown signals (PCSs) are specifically designed to improve pedestrian safety at intersections. However, the cost of retrofitting an existing intersection with a PCS, or the cost of including a PCS in a new intersection, may discourage PCS use at locations with a low pedestrian demand. Surprisingly, however, these devices appear to have positive safety benefits for a demographic group that is poised to increase by 20 percent nationally over the next two decades (2020-2040): older population age 65 years and above. Between 2012 and 2016, the number of licensed older drivers (65 + years) increased by 16 percent (NHTSA, 2013). Using the state of Michigan as a case study, this paper reports on the safety impacts of PCSs for motorists age 65 + years.
Methods
The study used ten years of crash data (five years before and 5 years after PCSs installation) from 93 intersections with PCS (treated sites) and a comparison group of 97 intersections without countdown timers (but with pedestrian signals). A before-after with comparison group methodology, crash proportions and cost benefit analysis were used to conduct the PCS evaluation on senior motorists.
Results
The study indicated that the inclusion of PCSs significantly reduced total (all severity) and injury only crashes for drivers aged 65 and above by 18 and 29 percent (p < 0.05) respectively. Monetization of crash impacts also suggests that inclusion of PCSs when installing a pedestrian signal yields a benefit-cost ratio ranging from 181 to 604 depending on the service life of the device. The focus on motorists aged 65 + is noteworthy, as PCSs did not necessarily have a statistically significant impact when motorists of all age groups are considered.
Conclusion
Localities may wish to consider PCSs when there are concerns about senior motorist crashes at intersections since they also benefit from PCSs. Because PCSs may be installed at locations with other safety treatments, a synthesis of other locations' experiences with PCSs would complement the results of this study.
Language: en |