Road Infrastructure Inspections to Assess the Road Network According to the iRAP/EuroRAP methodology

Abstract

The project aims at making a quality and quantity safety assessment of some road infrastructures of the Italian primary network according to the iRAP/EuroRAP methodology, with the objective of understanding which investments and speeds should be put in place to save lives and work towards international road safety targets. The indicator used for the assessment is the five-star rating system (5 stars = safe road, 1 star = unsafe road with major critical issues). The main result from this evaluation is the Star Rating, a simple and objective evaluation of the road safety level for vehicle occupants, motorcyclists, cyclists and pedestrians. It represents an objective measure of the probability of a road crash occurrence, as well as of its seriousness. A further result is the preparation of the Safer Roads Investment Plans (SRIP), which include a series of countermeasures to make the assessed roads safer. The preliminary activity to select the road sections to be inspected consisted in drafting a crash risk rate map of the Trans-European Road Network in Italy. The road traffic crash data evaluated regard the last three-year period (2017-2019). The study of the crash rate risk map of the Italian region Lazio allowed to identify about 300 km of road network, specifically 95.8 km of single carriageway roads and 113.5 km of dual carriageway roads. Inspections were carried out by FRED Engineering company; the collected data were then processed through the ViDA software in order to be assessed according the iRAP methodology. The results show a high risk level on the entire road network inspected for all road users. In total, 63% of the examined road network were rated 1 or 2 stars for vehicle occupants, but for motorcyclists the percentage of critical sections rises to 93%. The iRAP process ends up with the Investment Plans for the assessed road network, which include the possible countermeasures to be used in the various road sections for their Star Rating improvement. The objective is that all the roads are rated three stars or better. In light of these findings, a whole series of sensitivity analysis was carried out to highlight the importance and the impact of the input data on the deliverables. The considerations arising from this analysis will also be used to propose changes and/or possible releases of the ViDA assessment software.