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Road safety audits

Road Safety Audits (RSA) are about road crash prevention. Their purpose is to ensure that the design of new roads and/or traffic schemes provides a high level of safety, aimed at preventing injuries, or at least, reducing their severity should they occur. RSA proactively applies the principles developed through accident remedial programmes that have been found to be effective.

Increasingly, RSAs are being done in most parts of the world. Some countries have developed manuals to guide practice and carried out RSAs for years while others are initiating programmes for the first time. In light of this global interest, efforts are underway now to develop a more formalized and systematic approach with practitioners worldwide sharing knowledge and experiences.

The cost of a RSA can range from less than a thousands dollars for small projects to ten thousands dollars or more per stage for a major road project. This may be the equivalent to less than 4% of the road design cost (although the percentage could be higher on minor projects) As the design costs can be in the order of 5 to 6 % of total implementation costs for larger projects, the increase in total project cost is usually quite small. This is disputed by the results of the few cost-benefit analysis done, which clearly show that a RSA can save lives and limit injuries. The Danish Ministry of Transport conducted one such analysis in 1995 to 1996. It concluded that a RSA is beneficial with a return of 146 per cent within the first year after completion of construction. A study done in the UK, found that on sites with audited designs, the average annual number of casualties per site dropped from 2.08 to 0.83 compared with non-audited sites which dropped from 2.6 to 2.34.

In addition, a well-done RSA can enhance road safety engineering, reduce the need to modify new schemes after they are built, establish standard safety improvements and procedures and ensure the security requirements of vulnerable road users.

What is it?

There is a narrow consensus on the definition of RSA. Austroads (the association of Australian and New Zealand road transport and traffic authorities) defines it as a "formal examination of a future road or traffic project, an existing road, or any project which interacts with road users, in which an independent, qualified examiner reports on the project's potential for road crashes and safety performance." Most practitioners agree that a RSA can be qualified as:

  • A systematic formal review process (and not an informal check) based on an organised procedure described in a guideline, manual or similar publication;
  • Carried out by professionals independent of the design;
  • Done on relevant projects at appropriate stages and restricted to road safety issues.


The main objective of RSA is to ensure a high level of safety for all new road and traffic schemes. Secondary objectives are:

  • To reduce the whole-life costs of a scheme; unsatisfactory designs can be expensive to correct after they have been built;
  • To minimize the risk of road crashes on the adjacent road network, particularly at tie-ins, as well as on the new road scheme;
  • To enhance the relevance of road safety engineering in road and traffic scheme design work;
  • To promote the consideration of the safety of all road users in all new and existing schemes.

Components of an audit

Cycle lane signs in Tokyo.The RSA process is subject to the institutional framework within which it is to be conducted. In some countries, RSA is voluntary and in others it is statutory. Normally, it requires the involvement of the "client" (or owner of the project), the "designer" and the "auditor". There are generally three main phases in conducting a RSA:

Ordering a RSA

The designer of a road/traffic project may order a RSA while others prefer the client to order it thereby ensuring the independence of the RSA team. Normally a RSA team with essential safety engineering skills is appointed. These skills should include an understanding of traffic engineering, traffic management, road design, construction techniques, road user behaviour and human perception.

The RSA review process

The RSA team reviews all materials made available by the designer and/or client, and performs inspections and investigations as may be necessary. Relevant checklist(s) may be used. The RSA team leader (or specialist auditor in the case of one-person audit) collates all information, including inputs from audit team members and reports any road safety problems.

Some countries consider that the auditor should only state the problem. It is then the responsibility of the designer and the client to either address or not, although the auditor may suggest an approach towards solving a safety problem. Other countries want auditors to propose solutions to any problems. In this case, auditors may take into consideration both the potential harmful effects of the problem and the cost to repair it. If the solution is relatively expensive, the auditor may not report minor problems.

The audit results are described in a RSA report, which is then submitted to the designer with a copy to the client, if required. The RSA Report is final and should not be altered once it is submitted.

Finalizing a RSA

The designer considers the indicated problems and may request a clarification meeting with the auditor. Any disagreements are presented to the client who makes the decision on a course of action. Some countries require the designer/client to reply formally to the RSA report. Generally this is a good practice, particularly if due diligence is to be proven in litigation actions. In the reply, the designer/client should describe the approach to solve or attenuate the identified problems. The designer/client may choose not to act for specific reasons of which "restricted budget" may be a valid reason.

When to do an RSA

There are generally four stages at which a road safety audit can be conducted: 1) feasibility (planning) stage, (2) layout design stage, (3) detailed design stage, and (4) pre-opening stage. Early auditing can achieve better results at much lower remedial cost.

There is a fifth stage that is the audit of existing roads. Whilst not included in the early development of RSA, which targeted new roads, several countries notably Australia and new Zealand have now introduced this type of audit. There are two aspects to this stage. First problems overlooked by the RSA Team during the preceding stages may become evident during the first weeks or months of operation. Secondly, this stage is also applied to an existing road, in which case it is sometimes termed "Road Safety Assessment" rather than audit. This assesses a route or a network for problems and potential hazardous locations.

Road safety remedial projects are identified through prioritization processes from the planning through to implementation phases subject to a RSA. It is worth taking note that an audit of existing roads may have the added benefit of a history of existing safety deficiencies, for example road crash statistics, to help identify problems.

Training programmes

A RSA requires road safety professionals from different backgrounds to work as a team to identify road safety problems. Some countries have developed specific education programmes for auditors, which is generally a short course (3-day) format.

Further Reading

Asian Development Bank. 2003. Road Safety Audit for Road Projects - An Operational Toolkit. Manila, Philippines.

Austroads. 2002. Road Safety Audit - Second edition. Sydney Australia

COLTO. May 1999. South Africa Road Safety Manual. Committee of Land Transport Officials, South Africa.

Danish Road Directorate 1996. Manual of Road Safety Audit. Ministry of Transport. Copenhagen, Denmark

Department of Transport. 1994. Design Manual for Roads and Bridges, Volume 5, section 2, Parts 2 and 3: Road Safety Audits: HD 19/94 and HA 42/94, London, Great Britain.

Federal Highway Administration 1997. Road Safety Audits. Part 1 and Part 2. Washington DC.

Government of Nepal. 1997 Road Safety Audit Manual. Departments of Roads, Ministry of Transport, Nepal.

Institution of highways and Transportation. 1996. Guidelines on Safety Audit of Highways, London, Great Britain.

Ministry of Transport and Highways. Sri Lanka: Road Safety Audit. (Checklists prepared by SWEROAD)

PIARC 2001 Road Safety Audits. La Defence Cedex, France

Public Works Department (JKR). 1997. Road Safety Audit: Guidelines for the Safety Audit of Roads and Road Projects in Malaysia. Kuala Lumpur.

Transfund New Zealand. 1999. Interim Procedures for Safety Audit of Traffic Control at Roadwork Sites. Report No. RA98/6895, Wellington, New Zealand