Evaluation of Michigan's Engineering Improvements for Older Drivers

Michigan crash data shows that over the past decade (2002-2011), while overall fatal crashes decreased by more than 30 percent for all drivers, they only decreased by 7.8 percent for elderly drivers. As a result, involvement of older drivers in these serious has grown in terms of both frequency and proportion. The increasing involvement of older drivers likely reflects the increasing number of older persons in the population. Older-driver involvement in crashes can be expected to continue rising as the aging "baby boom" generation forms an increasing proportion of the driving and general population. The higher fatality rates associated with older road users may reflect the increased fragility of older persons. In response to these trends the Michigan Department of Transportation (MDOT) has concluded that continued safety improvements for older drivers and pedestrians should be implemented to counter the potential for a major increase in older driver fatalities as the population ages and attempts to maintain its high level of mobility. Over the past several years, MDOT in coordination with the Governors Traffic Safety Advisory Commission (GTSAC) has instituted several programs aimed at addressing the needs of older road users. These programs are outlined in the Michigan Senior Mobility Action Plan. This plan focuses on implementing a multidisciplinary approach (e.g. engineering, enforcement, education, and emergency services) towards improving safety and mobility. Many of these programs to assist older road users have the additional benefit of helping the general driving population. A number of studies related to the engineering improvements for older drivers to be evaluated in this research have been conducted across the US. For example, Chow et al (2007) evaluated the benefits and impacts of Clearview lettering. The researchers concluded that relevant benefit of the use of Clearview font include improvement in legibility distance of nighttime guide sign. The benefit is supported by the fact that halation and blooming is reduced. It provides easiness for drivers, especially older driver, to read signs and markings faster. Another example of studies on engineering improvements for older driver include Kohinoor and Mike (2012) who examined the safety impact of converting pedestrian signals to add the countdown feature in Arizona. Our research team will conduct a comprehensive literature review to uncover similar studies on engineering improvements that benefit older drivers. Since Michigan implemented these improvements for a number of years now, it is important that a comprehensive evaluation of their effectiveness be performed. This research may lead to the local agencies within Michigan implementing the improvements that prove to be most valuable. MDOT would be able to determine if continuing these engineering improvements have a safety benefit for older drivers, are cost effective, and have had an impact on the overall driving population. The results would have a direct impact on the level of funding and what infrastructure improvements should be continued and/or initiated. The research would develop Crash Modification Factors (CMF) for older drivers related to these improvements and develop Safety Performance Factors (SPFs) for older drivers as they relate to these improvements.