Safe Travels: Evaluating Mobility Management Traffic Safety Impacts

Abstract

This report investigates the relationships between mobility (the amount people travel) and crash risk, and the traffic safety impacts of mobility management strategies that change travel patterns to increase transportation system efficiency. Although many factors affect traffic crash rates, evidence summarized in this report indicates that all else being equal, per capita traffic crash rates increase with per capita vehicle travel, and that mobility management strategies tend to provide safety benefits. Strategies that reduce per capita vehicle travel tend to reduce overall crash risk. Mode shifting tends to reduce per capita crash rates by reducing risk per mile and total mileage. Shifting vehicle travel from moreto 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 provide significant safety benefits. Conventional traffic risk analysis tends to understate the safety impacts of changes in mileage. 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.