Purpose

The aim of this policy is to reduce the risk of incidents where objects are thrown from overpass structures onto arterial roads or freeways. The identification and treatment of sites will be undertaken in a systematic, cost-effective manner.

Scope

This policy applies to all arterial road and freeway overpass structures where VicRoads is the coordinating road authority.

Context

The incidence of object-throwing from overpass structures is generally both irregular and infrequent. However, the potential consequences can be fatal. These occurrences are proportionally estimated to represent less than 0.01% of serious and fatal crashes on Victoria’s road network. The majority of incidents are opportunistic and these are easier to prevent by removing loose material near the structures. Intentional acts cannot always be prevented and engineering treatments alone will not prevent intentional criminal activity. Intentional acts of object-throwing are commonly repeated over a short period, suggesting offenders tend to repeat the activity unless they are caught or likely to get caught due to police, media and public attention.
High risk factors, in combination with higher traffic volume and speed, generally warrant greater concern. The height of the structure is less of a factor than the speed of vehicles passing underneath. There is an observed correlation between throwing objects and incidents of graffiti and enforcement options can be used to help deter this criminal activity. The consequences of these actions can be brought to the attention of the community.

Policy

The policy is intended to provide a guide to reduce the risk associated with incidents involving objects thrown from overpass structures.
A standard risk assessment will be used for reducing risks associated with opportunistic incidents of throwing objects from overpass structures. Generally resources will be focussed at high and extreme risk sites.

VicRoads will undertake the risk assessment of sites where at least one object-throwing incident has been reported. Consideration may also be given to undertaking a risk assessment if, in the vicinity of the site, there are multiple reports of problems relating to graffiti, vandalism, or unlawful activity by youths over a 12 month period.

Treatments Options

Existing Structures

A site with assessed risk of medium or higher will require consideration of appropriate risk reduction methods.Although protective screens will not provide 100% guarantee of safety for road users, screening will generally provide the highest available level of safety given physical, social and economic constraints. There is a range of other potential measures which need to be considered, implemented and monitored before protective screens should be considered as a solution for any sites. Risk reduction methods that are to be considered include:

• Awareness of issues and discussions with local authorities and community groups;
• Appropriate communication activities advising local residents of the issues regarding the dangerous practice of throwing objects from overpass structures;
• Education initiatives to target children;
• Improved public visibility;
• Improved maintenance practices in the vicinity of structures to remove loose stones, concrete fragments, litter and sundry foreign objects that could potentially be used as missiles;
• Covering stony embankments (grade permitting) with mulch with the possible inclusion of small shrubs;
• Replacement of timber and metal delineator posts in the immediate vicinity of the structures with lightweight plastic alternatives;
• Modification or removal of other road furniture that could be used as objects;
• Installation of lighting or enhanced lighting;
• Installation of video surveillance and signs; and
• Installation of protective safety screens.

New Structure

This policy recommends that a risk assessment of new overpass structures be undertaken at the project development stage of the project.

Treatment Proposals

The aim is to develop a treatment which will reduce the risk to low. Comparison of alternative proposals should include an analysis based on the cost effectiveness of the treatments in reducing the level of risk. If a relatively expensive treatment such as protective safety screen is recommended, it should be subject to a cost benefit analysis. The funding of any proposal will depend on its relative priority when compared with other road improvement proposals across the State.

Contact details

The contact detail for questions relating to the policy is:
Director Asset Management
VicRoads, Network and Asset Planning
3rd Floor, South Building
60, Denmark Street, Kew, Vic 3101