The Nuts and Bolts of a Road Safety Audit
Although many people want to help improve road safety around the world, few actually know the nuts and bolts of accomplishing this goal. Wilson Arias-Rojas, Civil Engineer and Surveyor with 17 years of experience working for the Department of Justice of Puerto Rico and as a professor at the University of Puerto Rico, contributes insight into how a road safety audit is conducted. With this insight, urban dwellers can better understand the components of what make their roadways work or not work, and can help city leaders and decision makers create more effective policies.
Why do road safety audits matter?
Traffic crashes are a serious problem throughout the world in social, health and economic terms. Traffic fatalities are the second leading cause of deaths for the economically active population – those employed or actively seeking employment – in many countries. The World Bank considers road safety deaths to be of endemic proportions. Between 50 and 200 people for each one million inhabitants are killed each year for in most developed as well as developing countries.
Working towards a solution
Road safety audits originated in the United Kingdom in 1980, making use of extensive Accident Investigation and Prevention (AIP) experience in that country and in response to successive legislation by various highway authorities to take steps to reduce the possibility of crashes. When AIP teams were successful in investigating accident problems on existing roads, they began using that experience to assess designs for new road schemes.
A road safety audit is a process for systematically checking the safety of proposed road transport projects. This includes inspecting sections of roadways, segments, isolated intersections, urban corridors, crossings of highways with train lines, and highways in school zones. The safety audits are taken from the road users' perspective and provide an independent assessment of the "anticipated" safety performance of a road transportation project at predetermined intervals by road safety specialists. However, the project design team remains ultimately responsible for the final design.
The Federal Highway Administration (FHWA), the Institute of Transportation Engineers (ITE), and the Association of Australian and New Zealand Road Transport and Traffic Authorities has defined a road safety audit as composed of these objectives:
- Ensure a high level of safety for all road users in all new road and traffic project.
- Reduce the whole-life cost of a project; shoddy design can be expensive to correct after implementation.
- Minimize risks of roads crashes on adjacent road networks, particularly at tie-ins, as well as on the new roads.
- Enhance the relevance of road safety engineering in road and traffic scheme design work.
To better understand this concept, the following images show a road safety audit at an urban intersection in Grand Rapids, Michigan. The photograph illustrates both geometric and operational problems that must be resolved.
Image courtesy of AAA Michigan.
- Deficient lighting
- Trees present inside the driver visual triangle.
- A single traffic light controls all traffic flows.
- Nonexistent signage.
- Two ways lanes. No "ONLY" lanes.
- Roadside Parking
The picture below shows the alterations to the intersection after the audit. The modifications are highlighted below:
Image courtesy of AAA Michigan.
- A change in geometry and post elevation.
- Removal of the tree to the side of the road.
- Traffic light were change from one face to three faces.
- Manual on Uniform Traffic Control Devices (MUTCD) compliant faces.
- ONLY lane arrow in the pavement indicating turns to the left side.
- Parking is prohibited at the roadside.
While everyday road users can imagine the two scenarios and appreciate how small changes to the design of the road can make their journey safer and more enjoyable, these changes also hold a broader significance. Meanwhile, city leaders and policy makers, in understanding the process of a road safety audit, can craft clearer, more effective policies and make roads safer for urban residents.