Road crashes are now recognised as a serious social and economic problem in most low and middle income countries where road design is often focussed on the needs of motorists and do not usually cater adequately for the needs of other road users e.g. pedestrians, cyclists, para transit. Sometimes it is because design standards are outdated and not based on current international best practice. Sometimes it is just not possible to comply with the standards e.g. in built-up areas or difficult terrain. In addition, when roads are rehabilitated, it is often only the running surface that is improved, leaving horizontal and vertical curvature unchanged. The much higher speeds now possible on such resurfaced roads often lead to increased occurrence of crashes . Even where standards are generally acceptable, inappropriate combinations of design elements can sometimes lead to unintended dangerous situations.
The “Safe System Approach” has been devised to focus on the Human Factors and the interface between road users and the road. In this approach road design has to be adapted to road users abilities and limitations. A number of techniques and processes have been developed in the last two decades which can be applied to road design. EU Directive no. 2008/96 on road infrastructure safety management includes guidance on the elements of a Safe Systems Approach. Contents of the Directive include:
- Road safety impact assessment (RIA);
- Road safety audit for the design stages of roads (RSA);
- Safety ranking and management of the road network in operation, including management of high risks road sections (BSM);
- Road safety inspections for existing roads (RSI);
- In-depth crash analysis (IDS).
One of the most important aspects of the Safe Systems Approach is Road Safety Audit (RSA). RSA is a term used internationally to describe “an independent review of a road project to identify road or traffic safety concerns”. RSA can be regarded as part of a comprehensive quality management system i.e. a formal examination of a road or a traffic project. RSA represents a pro-active (preventive) approach that should be included in any road design process and comprises:
- A formalised process;
- An independent process;
- Carried out by someone with appropriate safety experience and training;
- Restricted to road safety issues of the road design thereby making it safer for all road users.
The output from an RSA is a formal report produced by road safety experts which identifies existing and potential road safety deficiencies and, if appropriate, makes recommendations aimed at removing or reducing these deficiencies. Within the audit process, experience proves that it is possible to reduce the number and severity of traffic crashes by addressing and eliminating potential dangers identified by the safety auditors .
According to the best practice, Road Safety Audits are most commonly conducted at the following milestones:
- Stage 1: draft design;
- Stage 2: detailed design;
- Stage 3: pre-opening of the road;
- Stage 4: early operation, when the road is in use.
RSA is is carried out on design drawings of proposed roads at various stage of design and eventually before the road is opened for public use.
Road Safety Inspection (RSI) is normally applied to existing road networks to identify areas for improvement. The output of RSI is also a formal report but in a different format to the RSA report.