Validation of a Simplified Road Assessment Programme Methodology

A Road Assessment Programme (RAP) is a procedure to assess the safety level of a road infrastructure based on the existing features/risk factors. A simplified RAP methodology using automated video image analysis has been previously defined. From the process, a Global Risk Score (GRS) was calculated. This paper aims to present the application and validation of the proposed simplified RAP methodology. A survey of 1220 km of the national motorway M-1/E30 road sections Kozlovichi (Poland border) – Minsk – Red’ki (Russian border) was performed in Belarus in September 2021. Validation of the procedure was carried out on M1/E30 by comparing the GRS values obtained and road traffic crash (RTC) data history. Three datasets have been used during the validation process, in particular: GRS dataset 2021, historical series of RTC recorded on the portion of interest of the M1 for the period 2017-2019, and data related to traffic flows for 2015. In order to compare the GRS values and the RTC data, different models were calibrated. A generalized linear modeling techniques (GLM) were used to fit the models, and a negative binomial distribution error structure was assumed. The variables AADT, segment length, and GRS were positively linked to the expected number of RTC frequency. The validation process demonstrated a positive correlation between the GRS values and the expected number of RTC. It has been shown that increasing the value of the GRS leads to an increase in the expected number of RTC.