Speed Limits and Pavement Friction: A Theoretical and Experimental Study

Background: As is well known, in road construction, quality acceptance procedures and quality assurance/control procedures during operations (for maintenance and rehabilitation purposes) focus on material quality from a mechanistic and safety perspective. This latter usually entails the consideration of friction and surface texture indicators. When friction requirements (e.g., side friction coefficients measured through the SCRIM machine) are not satisfied, road agencies have two main options: closing the traffic or having lower speed limits. The first option is often unrealistic and challenging. It turns out that a new, often temporary, speed limit is required and appropriate methodologies are required to carry out this critical task. Aims and Objectives: Consequently, the objective of the study presented in this paper is to set up a methodology aiming at engineering-based assessments of speed limits based on actual friction values. Original and consistent algorithms are set up to solve theoretical and practical issues. Result and Conclusion: The main contributions of this study include: (1) setting up a methodology for friction-based assessment of speed limits through innovative speed-friction relationships and criteria; (2) utilising the methodology for a case study; (3) providing recommendations for the application. Results prove that the algorithms set up are reasonable and well-grounded in logic. They can benefit both researchers and practitioners.