Model of the Performance of a Roadway Safety Fence and Its Use for Design

Abstract

The optimization of roadway safety design by experimental means is expensive and time consuming. Computer simulation of such complex engineering systems improves understanding of how and why the system behaves as it does, aids in decision making, and reduces development costs and time involved. The simulation presented is based on a computer model developed from a study of the results of full-scale experiments of impact on the Brifen wire-rope safety fence (WRSF). The code comprises a dynamic vehicle model and a quasi-static fence model interacting in time through the important collapse mechanisms of the system. The principles governing them are described and their inclusion is validated by demonstrating good correlation between the predictions of the simulation and the experimental test data. Sensitivity studies show that the performance of a WRSF is particularly sensitive to the impact conditions of vehicle speed and angle and the design parameters offence height, post spacing, post strength, and rope pre-tension. The sensitivity work is extended to show that for fences installed with a low rope pre-tension, performance may not be significantly impaired if rope pre-tension is not maintained. However, significant gains in fence performance may be made should a fence be installed and maintained with a high rope pre-tension. The use of the simulation in assessing cost-effectiveness of alternative designs in achieving a target performance is also demonstrated.

The Influence Factors of Highway Traffic Accident and Accident Rates Model

“…Using hierarchical tree regression method, Matthew et al quantified the impact of road characteristics on accident rates, research result showed that the road line shape and road conditions are the most important factors in traffic accidents [3]. Other run-off-roadway accident studies have examined particular roadside features such as roadway guardrail systems, utility poles, bridges, sign supports, side slopes and ditches and fences and their effect on the frequency and severity of accidents [4][5][6].…”

Validation of a computer simulation of the impact performance of a wire rope safety fence

“…The comparisons made cover much more detail than the first study and provide substantial evidence for validating the individual models used within the simulation. An outline of the early development of the work, including some design implications, are presented in a conference paper published by the Transportation Research Board of America [4].…”