LANE CHANGE/MERGE CRASHES: PROBLEM SIZE ASSESSMENT AND STATISTICAL DESCRIPTION. TECHNICAL REPORT. FINAL REPORT

Abstract

This document presents problem size assessments and statistical descriptions for lane change/merge (LCM) crashes and two key subtypes of the LCM crashes. The LCM crashes are a potential target crash of high-technology Intelligent Vehicle Highway System (IVHS) avoidance countermeasures. To elucidate potential countermeasure applicability, the LCM is divided into two types: angle/sideswipe and rear-end LCM crashes. The emphasis of this report is on the angle/sideswipe LCM crashes. This subclass is likely to be most amenable to prevention by an obstacle detection system. Principal data sources are the 1991 General Estimates System (GES) and Fatal Accident Reporting System (FARS). LCM problem size is assessed using such measures as number of crashes, number and severity of injuries, number of fatalities, involvement rate, and involvement likelihood. Problem size statistics are provided for four vehicle type categories: all vehicles, passenger vehicles (i.e., cars, light trucks, light vans), combination-unit trucks and medium/heavy single-unit trucks. Angle/sideswipe LCM crashes are described statistically primarily in terms of the conditions under which they occur (e.g., time of day, weather, roadway type, relation to junction) and, when data are available, in terms of possible contributing factors.