Road Safety Analysis

Road Safety Analysis is the systematic study of traffic crashes, near-misses, and risk factors to identify dangerous locations, understand collision causation, and develop evidence-based countermeasures that reduce fatalities and serious injuries. Using georeferenced crash records, road inventory data, traffic volumes, and speed data, analysts apply statistical methods to distinguish locations with genuinely elevated risk from those with random crash clustering. GISGISGeographic Information Systems (GIS) enable users to analyze and visualize spatial data to uncover patterns, relation...-based crash mapping visualizes collision locations and enables spatial analysis techniques including hotspot identification, network screening, and corridor safety assessment. Crash modification factors (CMFs) quantify the expected safety effects of specific countermeasures like roundabouts, rumble strips, or protected left turns. Before-and-after studies using Empirical Bayes methods evaluate whether implemented improvements achieved expected crash reductions while accounting for regression to the mean. Applications include Highway Safety Improvement Program (HSIP) analysis required for federal safety funding, Vision Zero action plans that target eliminating traffic fatalities, systemic safety analysis that identifies road characteristics associated with severe crashes network-wide, pedestrian and bicycle safety assessments, and work zone safety planning. Safe System approach principles increasingly guide safety analysis, recognizing that human error is inevitable and road design must prevent errors from becoming fatal crashes.