Whole Life Cost-Benefit Analysis for Median Safety Barriers Task 2 - Structural Consequences - Executive Summary

Introduction

TRL Limited has been commissioned by the Highways Agency to identify, investigate and report on incidents in which the breach of a safety barrier has occurred and resulted in damage to an item of roadside equipment.  This report identifies four specific accidents and summarises the costs associated with the repair of the safety barrier and item of roadside equipment, traffic delay, traffic management and any resulting injuries.

Executive Summary

TRL Limited has been commissioned by the Highways Agency to identify, investigate and report on incidents in which the breach of a safety barrier has occurred and resulted in damage to an item of roadside equipment.  The costs associated with repair, traffic delay, traffic management and any resulting injuries have then been evaluated.

In order to obtain detailed information relating to the damage and costs associated with structural impacts, one area of the Highways Agency's Network, the M25 Sphere, was identified, and details of incidents involving safety barrier breaches and subsequent structural damage were collated.  From this list of incidents, the following were selected for further analysis:

In each case, details of damage to the barrier and the item of roadside equipment were collated and the costs associated with restoring the site obtained.  As the time for which vehicular access was restricted was known at each incident site, the traffic delay costs were also calculated.

In addition a letter was also distributed to all of the Highways Agency's regional Traffic Operations Departments, their Agents and their Term Maintenance Contractors to obtain their experiences from such incidents. 

The report concludes that the costs associated with an incident are highly dependant on the impact parameters surrounding the incident, and the costs associated with the individual costs associated with repairs, traffic delay and the severity of the resulting injuries caused by the incident.  Each potential hazard should be assessed on a case-by-case basis and each of these factors quantified using a statistical approach, including the implementation of a risk analysis procedure.

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