Reduction in Nonfatal Injury Crashes After Implementation of Anti-Icing Technology

Abstract

Several published papers and studies have shown that adverse weather conditions contribute to motor vehicle crashes and have an overall negative effect on highway safety. No publications were found to demonstrate the positive effects of winter maintenance anti-icing policies on safety for an entire network, such as a state highway system. Following a decision in the 2005–2006 season, the Connecticut Department of Transportation (DOT) converted from deicing to anti-icing policies. In this paper, aggregated motor vehicle crashes with nonfatal injuries are analyzed graphically to determine if winter weather safety was affected by the Connecticut DOT’s switch from deicing with a sand–salt mix to anti-icing procedures that included switching to salt only. A survey of the states surrounding Connecticut provided evidence that the Connecticut DOT had applied winter deicing chemical types and quantities in a similar manner to its neighboring states. This Connecticut study concluded that crashes with nonfatal injuries during winter seasons, in all kinds of weather and road conditions, declined by 19.2% between seven winters (1999–2000 through 2005–2006) in which a sand–salt (7:2) mix was used and seven winters (2006–2007 through 2012–2013) in which only salt was used and that the same types of crashes that occurred when roads were snow, slush, or ice covered declined by 33.5%. Also, there was an immediate additional reduction in nonfatal crashes with injuries after the Connecticut DOT converted to anti-icing in the 2006–2007 winter. Even considering the increase in safety technology employed by modern vehicles, it appears that anti-icing likely reduces the amount of time that roads are slippery and therefore reduces serious crashes.