The impact of the repeal of Michigan's universal helmet law on traumatic brain injury: A statewide analysis

In April of 2012, Michigan repealed its 35-year-old universal motorcycle helmet law in favor of a partial helmet law, which permits motorcyclists older than 21 years old with sufficient insurance and experience to drive un-helmeted. We evaluated the clinical impact of the repeal. The Michigan Trauma Quality Improvement Program's trauma database was queried for motorcycle crash patients between 1/1/09–4/12/12 and between 4/13/12–12/31/14. There were 1970 patients in the pre-repeal analysis and 2673 patients in the post-repeal analysis. Following the repeal, patients were more likely to be un-helmeted (p