2018 - USA - Relationship Between Speed and Roughness

Road and traffic factors that influence speed have attracted interest for modeling vehicle
fuel consumption and traffic safety. While the influence of geometric design and traffic operation factors have been well studied, the relationship between pavement surface roughness and vehicle speed was not well established in previous studies, mainly because of data limitations. The authors applied a new dataset, Naturalistic Driving Study (NDS) data of the Strategic Highway Research Program 2 (SHRP 2), for studying the roughness-speed relationship. A method was developed to identify the roughness-speed relationship under different road and traffic conditions. The International Roughness Index (IRI) was employed to describe the pavement roughness condition in this research. The new method can be applied to reveal a roughness-speed relationship of different road and traffic conditions with the SHRP 2 NDS dataset. The case study shows that pavement surface roughness impacts traffic speed for different full-access control road scenarios with the listed properties. The research conducted will give other engineers a guidance on how to develop a method to predict speed at different Levels of Service (LOS) given similar road properties on an all access roadway.