Relationship Between Road Roughness and Vehicle Speed

Abstract

In the past, numerous researchers and pavement proffesionals tried to find an analytical relationship between the road roughness and the vehicle speed which were measured on the same test sections. In HDM-4, special models were developed, in which maximum limiting speeds relative to road roughness condition were calculated. In this paper, a brief review of significant research conducted around the world that analyzed the influence of increasing road roughness, expressed through IRI, on the change of vehicle speed values, was given. The benefits and drawbacks of the results from previous studies were outlined, and the most important equations that define the relationship between the IRI and vehicle speed were presented. It has been found that the effect of pavement roughness on the vehicle speed is very small on the roads with IRI values less than 5m/km, such are usually the roads located in most developed countries.