Association Between Older Drivers' Signs and Motor Vehicle Crashes in Japan.

Area of Science:

• Traffic Safety
• Gerontology
• Public Policy

Background:

• Japan uniquely encourages older drivers to display an "older drivers' sign" to enhance traffic safety.
• Despite discussions on ageism, the actual safety benefits of this sign remain uninvestigated.

Purpose of the Study:

• To investigate the association between displaying the "older drivers' sign" and the risk of rear-end collisions among elderly drivers.
• To determine if the sign is an effective traffic safety measure for drivers aged 70 and above.

Main Methods:

• A nationwide case-control study analyzed police-reported traffic crash data from 2014-2023.
• Cases were rear-end collisions; controls were angle collisions involving drivers aged 70+.
• Adjusted odds ratios were calculated, considering crash time, driver sex, and age group.

Main Results:

• The proportion of drivers displaying the sign was similar in both cases (38%) and controls (39%).
• The adjusted odds ratio for rear-end collisions among sign-displaying drivers was 1.08 (95% CI: 1.04-1.12).
• Sign display was slightly more common in cases than controls, and higher among women and older age groups.

Conclusions:

• Displaying the "older drivers' sign" is not associated with a reduced risk of rear-end collisions.
• This traffic safety policy may not be effective in preventing crashes among older drivers.
• Alternative interventions are necessary to improve traffic safety for the elderly.