Measurement of visibility loss due to splash and spray: porous, SMA and conventional asphalt pavements

Abstract

Road traffic accidents are a major problem for the safety, well-being and economies of Southeast Asian countries. In Thailand, many accidents are caused by environmental or road conditions. Poor visibility on wet pavement is a major cause of accidents. Accumulated water on wet pavement surfaces creates the ‘splash and spray’ effect, resulting in visibility loss. The main objective of this study is to develop simple methods for measuring and comparing visibility loss between conventional dense-graded asphalt, stone mastic asphalt (SMA) and porous asphalt (PA) pavements. The light reduction method (LRM) and the colour changing method (CCM) were found to be the most appropriate tests for the measurement of visibility loss. Test results from both methods reveal that visibility loss is significantly greater for the conventional dense-graded pavement than for the SMA and PA pavements. Models for predicting the percentage of visibility loss were also developed and can be useful for improving road safety.

Keywords:

• visibility
• spray
• splash
• pavement
• light reduction
• colour changing