Assessing Road Users’ Acceptable Levels of Service

This paper presents the methodology and outcomes of 11 separate investigations that were undertaken from 1998 to 2004 in order to assess road users� expectations of the levels of service on roads in Australia. Road user groups, or panels, ranging from eight to forty three people, represented the communities that used particular road types in the assessment process. These roads ranged from unsealed and sealed local roads to freeways. The road users were surveyed for their assessments of levels of service. All investigations covered the assessment of the factors that influence road users� perceptions of levels of service and quantitative assessments of the maximum acceptable level of rideability or roughness of the roads. The investigations have shown so far that communities often have unique perceptions and requirements. In reviewing all 11 investigations, rideability ranked as the third highest factor thought to influence road users� perceptions of road conditions after potholes and safety. The road user surveys provided estimates of acceptable roughness based on: (1) rating and roughness relationships; and, (2) the % of acceptability and roughness relationships. The relationships from (2) were usually more statistically significant and a better fit to the data than the relationships from (1). However, in using the relationships from (2) to estimate acceptable roughness there is the issue about what levels of % of acceptability are used to set roughness limits. The estimated acceptable roughness was also found to have an observable tendency to increase with reducing the test speed.