By systematically inspecting roads, countries can develop an understanding of the level of risk that is ‘built in’ to their road networks. This provides a basis for targeting high-risk sections of road for improvement before people are killed or seriously injured. Inspections are especially useful when crash data is unavailable or unreliable.
iRAP inspections take two parts: road surveys and road attribute coding.
Surveys involve the collection digital, panoramic images or videos of the roads and GPS data. These images and data can be collected using a large range of equipment - from simple handheld devices to highly sophisticated survey vehicles.
The images are then used to record (or ‘code’) road attributes that are known to influence the likelihood of a crash and its severity. The inspections create a permanent video and database record that can be reviewed easily by local engineers and planners.
The attributes, which are recorded at 100 metre intervals, include:
Countries do not need to inspect every road in order to make a large difference; in India, about two-thirds of deaths occur on state and national highways which account for just 6% of the network.
iRAP encourages countries to focus inspections on their busiest roads, where the largest safety gains can be made. In Mexico, for example, assessments cover around 45,000km of federal roads, which is a little more than 10% of the nation’s roads (and around one third of paved roads).
To enable the cost-effective assessment of roads, there is a global network of accredited suppliers who are capable of competitively bidding to undertake high-quality inspections and coding.