Councils are being urged to consider increasing their use of high friction road surfaces following new research that has found that the average thinking time to brake and stop is double than that previously thought. This results in a significant increase in vehicle stopping distances.
The road safety charity Brake asked transport research agency TRL to investigate the time taken by car drivers to perceive, recognise and react to emergency situations. TRL reported that the average thinking time is 1.7 seconds. This is more than double the 0.67 seconds set out in the Highway Code.
Brake have calculated that this means that the average total stopping distance – including thinking and braking distance – is an extra 2.75 car lengths (11 metres) at 30mph and an extra 3.75 car lengths (15 metres) at 40mph, compared with the distances used in the Code. This difference rises to an additional 6.25 car lengths (25 metres) at 70mph.
“The increase in real-time stopping distances emphasises the need to have road surfaces that offer a high level of skid resistance particularly approaching junctions and pedestrian crossings”, said Howard Robinson, chief executive at the Road Surface Treatments Association (RSTA). “High friction surfacing is a well proven road surface that makes potentially high risk road locations far safer for both pedestrians and drivers by providing a skid reduction of up to 50 percent. Unfortunately due to perceived concerns over cost and durability many councils have reduced significantly their use of high friction surfacing in recent years”.
Some Councils have decided to use high polished stone value (PSV Asphalt). However, this does not offer the same level of skid resistance as high friction surfacing. A new British Board of Agrement (BBA) report has found the average service life of high friction surfacing is 12 years for cc cold applied systems and 8 years for hot applied systems, when it was previously thought it was 8 and 4.
“The BBA audit has significantly increased the expected average service life for high friction surfacing. This proves the long-term cost effectiveness of using this surface treatment,” said Robinson. “Using high friction surfacing saves lives and money particularly when you consider that the associated accident and investigation costs for non-motorway accidents is calculated to be £1.4 million. Councils must balance the cost of high friction road surfaces against their legal requirement to ensure that roads are safe and the financial cost of accidents.” Also the new Code of Practice – Well Managed Highway Infrastructure – is based on authorities making decisions after assessing risk so in this context the use of high friction surfacing is well aligned with the new code as it reduces the risk of skid related accidents occurring.
He continued: “The reality of the increased emergency stopping distances underlines the need to have a high level of skid resistance at potentially dangerous road junctions and crossings. Councils should reconsider and increase their use of high friction road surfaces.”