Preliminary Results towards Developing Thresholds for Pavement Condition Maintenance: Safety Perspective

Abstract

This paper focuses on examining the relationship between the International Roughness Index (IRI) and crashes to compare thresholds from a safety perspective with fuel efficiency perspective and pavement condition categories. Findings from the literature review, profile elevations captured using a laser profilometer along two test corridors in the State of North Carolina, United States (first one with concrete pavement and the second one with asphalt pavement), traffic volume from travel survey maps, and crash data maintained by the North Carolina Department of Transportation (NCDOT) were used for analysis and identification of preliminary thresholds from the safety perspective for pavement maintenance. Profile elevation data was processed to compute IRI values for each 100-m (330-ft) section along each selected corridor by direction. Crashes (all and under wet-pavement conditions) were identified for each section and added to the database. Scatter plots were generated to observe the trends in the number of all and wet-pavement crashes per mile by IRI. The average number of all crashes per section, wet-pavement crashes per section, all crashes per million vehicle miles travelled (MVMT) and wet- pavement crashes per MVMT were also computed for each corridor. Results obtained indicate that targeting and maintaining lower IRI to improve fuel efficiency may yield similar benefits from a safety perspective. Based on analysis using data for the considered corridors, they do not seem to vary by pavement type.