SAFETY EVALUATION OF ACCELERATION AND DECELERATION LANE LENGTHS

Prior research has revealed the safety importance of acceleration and deceleration lane lengths. A recent research report, entitled "Statistical Models of Accidents on Interchange Ramps and Speed-Change Lanes," documents the development of models relating accidents to ramp characteristics. This feature utilizes the information in this report to estimate accident frequencies for entire ramps, as a function of speed-change lane length, among other variables. An economic analysis procedure is then presented to evaluate the cost-effectiveness of extending speed-change lanes. The methodology presented allows a highway planner or designer to access the benefits of improving the safety of interchanges considered for reconstruction or when experiencing higher than average accident frequencies, without requiring existing accident records.