Since 2003, nearly 20 state, county, and city transportation departments have installed a new surface overlay that its developer—Cargill SafeLane Surface Overlay in Minneapolis—claims prevents frost and ice formation while sealing roadbeds to prevent degradation.
In a 2006–2007 report, Wilfrid Nixon, PE, president of winter highway maintenance consulting company Asset Insight Technologies LLC and an engineering professor at the University of Iowa, agrees that the “SafeLane” overlay does indeed improve road performance and increase safety.
Although cautioning that safety studies need to be conducted over a number of years to yield statistically significant results, the report found dramatic accident-reduction rates among 26 road and bridge test sites reporting data, including no weather-related crashes on the following test sites:The Blatnik Bridge on-ramp, linking the cities of Superior, Wis., and Duluth, Minn., where there were 20 crashes during the four years before the overlay was installed in 2005.The Ironwood Bridge on the US 20 bypass near South Bend, Ind., which had a long history of snow- and ice-related crashes before the overlay was installed. “If I can get 36,000 vehicles over that bridge in an ice storm without any crashes, it's worth its weight in gold,” says Steve Giese, operations manager at the Indiana DOT's Plymouth sub-district.The Wolf River Bridge in Crandon, Wis., which averaged three to four accidents a season before the overlay was installed in 2003. “Not one call about the bridge even being slippery, much less any accidents,” says Ron Cole of the Forest County highway department.
The report concluded that in nearly all cases, test sections remained clear of snow or ice at times when it was accumulating on untreated (control) sections of roads and bridges. When accumulation did occur on test sections, the snow and ice did not bond to the surface as often as on the control sections, resulting in easier plowing.
Treated segments of highway infrastructure maintained mobility for longer, and were returned to full mobility more easily than non-treated sections. However, such gains were less likely in wet, heavy snow or other high-moisture conditions.
In addition, there were no concerns with chemical slickness or slipperiness even when anti-icing chemicals were applied in conditions where slickness could be expected.
The report was commissioned by Cargill. Visit www.cargillsafelane.com to download a copy and learn about test site funding options administered by the Federal Highway Administration.
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