Road trials to determine the effect of de-icers on skid resistance

Highway authorities have a duty to keep highways free of ice and snow and endeavour to meet this duty by treating roads with de-icers. It is unlikely that de-icers will reduce grip to levels that would occur with ice or frost on the road, but concerns have been expressed by some road users that de-icers, particularly repeated applications that cause them to build up on the road surface, can adversely affect the skid resistance and increase the risk of skidding accidents compared with that in normal conditions This report describes a study in which a test methodology was established to investigate the effect of de-icers on skid resistance. The study included measurements of skid resistance on sites with hot rolled asphalt and proprietary thin surfacings that had been treated with de-icers. Four de-icers were included in the investigation, namely dry untreated rock salt, rock salts treated with Eco-Thaw and Safecote, and pre-wetted salt (rock salt pre-wetted with brine). The measurements were made with Highway Agency's Pavement Friction Tester (PFT) and a GripTester. The tests with the PFT showed that de-icers reduce skid resistance at low sliding speeds (20 - 40 km/h) compared with a wet road with no de-icer present, but at higher speeds (60 km/h and above) skid resistance with de-icer present is greater than on a normal wet road. The significance of these changes was assessed with reference to the seasonal increase in skid resistance from summer to winter and the investigatory level. The GripTester was found not to be suitable for general use in detecting any adverse effects due to de-icers. Since it was not possible to determine the effect of all the potential effects of de-icers on skid resistance, including a build up of de-icer and associated detritus during prolonged cold spells with repeated applications but little rain, further tests with the PTF are recommended. (A)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/184608749X
• Authors:
  • EVANS, M G
  • Jordan, R W
  • ROE, P G
• Publication Date: 2008

Language

• English

Media Info

• Pagination: R219
• Serial:
  • TRL Published Project Report
  • Publisher: TRL
  • ISSN: 0968-4093

Subject/Index Terms

• TRT Terms: Deicing; Frost; High risk drivers; Highways; Hot coated materials; Ice; Methodology; Safety; Skid resistance; Snow; Surfaces; Weather
• Subject Areas: Highways; Safety and Human Factors; I62: Winter Maintenance; I80: Accident Studies;

Filing Info

• Accession Number: 01115954
• Record Type: Publication
• Source Agency: TRL
• ISBN: 184608749X
• Files: ITRD
• Created Date: Dec 1 2008 7:35AM