Regional variation in motor vehicle accident reporting: findings from Massachusetts

Differences in motor vehicle crash reporting may affect geographic comparisons of motor vehicle crash rates. Substantial differences have been reported between nations and, within the United States, between states, but little is known about more localized differences. Data from Massachusetts' 45 largest municipalities indicate substantial local variation in the percentage of reported injury-producing crashes for which a police report is available, from fewer than 20% in the lowest decile to more than 85% in the highest. For a given municipality, the percentage of crashes with police reports in 1979 was highly predictive of the percentage with police reports in 1983.