01698338

Component

Traffic crashes occur usually because of the contribution of a combination of human, roadway/ environment, and vehicle factors. Pavement condition is closely related to the three factors as it is one of the most important roadway/environment factors and it affects driving behavior and vehicle performance at the same time. Previous studies have shown that pavement conditions have played an important role in safety. In this study, the authors develop four different safety performance functions to evaluate the effect of pavement roughness, which is measured by the International Roughness Index (IRI), on the number of crashes using the interstate highway data from five states representing different geographical and weather regions in the US: Arizona, Colorado, Florida, Maryland, and Michigan. The modeling results identify many significant variables including traffic volume and proportion of trucks, through lane count, shoulder type, median width, high-occupancy vehicle lane operation and HOV lane count, speed limit, area type along with IRI-related factors. The results indicate that the increased IRI (deterioration of pavement quality) contribute to larger numbers of total crashes. On interstate highways with speed limit of 70 mph and higher, the effects of IRI are relatively smaller. On the other hand, the effects of IRI increase with a larger traffic volume. Based on the modeling results, seven crash modification functions of IRI values by crash type and speed limit were estimated. The findings from this study are expected to be useful for both pavement and safety engineers to understand the relationship between IRI and safety on freeways.

This paper was sponsored by TRB committee ANB25 Standing Committee on Highway Safety Performance.

19-00735

English

8p

2019

Transportation Research Board 98th Annual Meeting

Digital/other

Figures; References (30) ; Tables

Crash modification factors; Freeways; Highway safety; Interstate highways; Mathematical models; Pavement distress; Roughness

International Roughness Index

Arizona; Colorado; Florida; Maryland; Michigan

Highways; Pavements; Safety and Human Factors

Transportation Research Board Annual Meeting 2019 Paper #19-00735

TRIS, TRB, ATRI

Dec 7 2018 9:52AM