A Procedure to Improve Safety Inspections Effectiveness and Reliability on Rural Two–Lane Highways

Road Safety Inspections (RSI) are recognised as an effective tool for identifying safety issues. However, due to the subjective nature of the process, they may give rise to disagreements which limit their effectiveness. In the framework of the IASP research program sponsored by European Commission, which is focused on rural two-lane highways, a RSI procedure aimed at improving the effectiveness and the reliability of the methodology has been defined. For this purpose, the research has been pinpointed on the inspection framework, on the inspectors and client roles and, with special emphasis, on the methodologies used for identifying and ranking the safety problems. In order to test the reliability of the methodology, the agreement of the results of the safety issues ranks produced by different inspectors has been addressed. Specifically, the statistic kappa has been used. Results show that there is a statistically significant level of agreement among inspectors for the majority of safety issues. The reliability of the procedure is satisfactory, especially if it is considered that the identification of the safety issues is a very complex task based on human evaluations and expertise not supported by instrumental measures