This report investigates the relationships between mobility (the amount people travel) and crash risk, and the safety impacts of mobility management strategies that change how and the amount people travel. Evidence summarized in this report indicates that per capita traffic crash rates tend to increase with per capita vehicle travel, and mobility management strategies can provide significant safety benefits. Strategies that reduce per capita vehicle travel, or shift travel from automobile to alternative modes, tend to reduce overall crash risk. Shifting vehicle travel to less-congested conditions tends to reduce crash frequency but may increase crash severity due to higher traffic speeds. Smart growth land use policies tend to reduce crash severity and fatality rates, although crash frequency may increase due to increased traffic density. Strategies that reduce traffic speeds reduce crash frequency and severity. Conventional traffic risk analysis understates many of these impacts. This analysis indicates that mobility management is a cost effective traffic safety strategy, and increased safety is one of the largest benefits of mobility management. (Author/publisher) Summaries of this research were presented at the 85th Transportation Research Board Annual Meeting (January 2006) and published in Injury Prevention, Vol. 15, Issue 6 (2009)
Abstract