• July 9th, 2012

Since the 1950s transportation professionals have been able to quantitatively assess project alternatives based on mobility, and more recently in terms of environmental impact. Limited means have existed to assess the safety performance of different design alternatives. To help address that gap, the Highway Safety Manual (HSM) was published by the American Association of State Highway Transportation Officials (AASHTO), culminating ten years of research and development by an international team of safety experts, academics, and practitioners.