Investigating Roadside Severity for Army Canal Highway in Baghdad City Using Risk Assessment Models

Roadside type is a crucial factor that affects road safety. This study aims to investigate the impact of 15 roadside types using the international Road Assessment Program (iRAP) model, which utilises the star rating system as a measure of road safety. The study, uniquely, focuses on using risk assessment models to evaluate the impact of roadside types on road safety in the case of a lack of crash data. The required geometric and traffic data were collected for two sections of the Army Canal highway in Baghdad city. The results showed that one roadside type (wire rope) improved safety performance, while others led to a reduction or limited effect on safety levels compared to the existing metal barriers in each section. It was observed that this option lowers the Star Rating Score (SRS) for section 1, driver side and passenger side, from 12.71 to 11.58 and from 12.62 to 11.42, respectively, corresponding to an 8.9% and 9.5% reduction in risk score, which was sufficient to shift the road section from Star Rating 2 to Star Rating 3. The study revealed similar results for section 2 with a different SRS.