|Rune Elvik, Poul Greibe
The report summarises current knowledge concerning the road safety effects of porous asphalt. A meta-analysis has been made of estimates of effect based on six studies. The results show that porous asphalt is not associated with statistically significant changes in the number of accidents. Knowledge concerning effects of porous asphalt on various risk factors has also been summarised. These effects are inconsistent and do not provide any basis for predicting effects on accidents. The main conclusion is that the effects of porous asphalt are poorly known.