Samenvatting
The South Dakota statute mandating helmet use by motorcyclist was modified, effective July 1, 1977, to effectively repeal the law for adult cyclists. The present report assesses changes in levels of helmet use and in state-wide accident experience between pre- and post- repeal periods. Although no detectable changes were observed in state-wide fatal, injury, or total crash rates, analysis of medical data for accident victims showed substantial evidence of negative import of helmet law repeal.