For some years it has been known that new asphalt surfacings have different skid resistance properties to surfaces that have been in service for some time. This is believed to be due to the presence of a film of bitumen binder on the new surface that is eventually removed by weathering and traffic. New types of surfacing introduced since the mid 1990s led to concerns that the risk of early-life skid resistance problems, and the time that any effects last, may have increased. Research identified physical phenomena that might lead to an increase in accident risk in some circumstances, and a subsequent accident analysis found that there was some evidence of a small increase in slight injury accidents in the first few months after laying a new surface on some types of road, but that these occurred in low-risk areas and were accompanied by a significant reduction in fatal accidents. Following on from those earlier studies, work has continued to investigate further the physical phenomena associated with the early life condition of new asphalt and to undertake a further accident analysis. This report provides an update to the initial accident analysis reported in PPR205 and includes sections of the HA network that were resurfaced between 2003 and 2006. The results for thin surfacings from this accident analysis are consistent with those reported in PPR205, which covered resurfacing works between 2001 and 2004, although the percentage changes are slightly lower than those reported in the previous study. The findings are also generally consistent with the physical phenomena that have been measured on new asphalt surfacings.

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