Evaluation of speed and accident reduction through increased traffic law enforcement

Abstract

Increased traffic law enforcement activities were implemented in six Texas counties in an effort to reduce traffic speed and accidents on selected rural roadways. Patrol activities, in addition to normal enforcement efforts, were continued for a 5 month period from August 13, 1979 until December 15, 1979. Speed and accident data were collected and analyzed throughout the study in order to assess the degree of reduction achieved. Data were also collected on several patrol measures in order to evaluate the effort necessary to bring about specified reductions in the traffic parameters of interest. The results indicate that increased patrol activity had the effect of decreasing mean vehicle speed and the percentage of motorists exceeding 55 mph over time. Mean speed was reduced 2.4%, and percent exceeding 55 mph was reduced 19%. Increased patrol activity, in reducing speeds, seems to have the effect of reducing the frequency and severity of accidents. Injury accidents were reduced 9.5%, and property damage accidents were reduced 11.3% on treatment roadways. Regression analyses indicated that a three variable model of speeding tickets per mile of roadway, total number of speeding tickets, and total number of warnings predicted the reduction in mean speed and percent exceeding 55 mph better than a single factor or other multi-factor models. A systematic relationship between patrol activity and accident reduction was not discovered. A set of administrative guidelines were developed based on a regression analysis on the variable speeding tickets per mile. These guidelines provide information regarding the expenditures required to bring about specified degrees of change in speed parameters and are applicable to programs employing increased patrol activity in rural areas over a 5 month period.