When winter roads become impassable, ambulances, fire engines, police and other emergency vehicles can’t perform their life-saving services. That’s bad enough, but the risk to life and limb goes far beyond the inability to respond to emergencies.
More than 116,000 Americans are injured and over 1,300 are killed on snowy, slushy or icy pavement every winter. It is no wonder, then, that the sight of salt trucks reassures citizens. Salt keeps roads open and safe.
A Marquette University study examined highway accidents in snow. Road salt reduced:
- Crashes by 88%
- Injuries by 85%
- Accident costs by 85%
Waterloo study on the Safety Impacts of Using Deicing Salt
A University of Waterloo analysis of collision data over six winter seasons (2000-2006) in Ontario.
We have long known the incredible benefits that road salt plays in ensuring safety and mobility during the winter months. However, this matter has only been studied on the most traveled highways in the past. In order to determine whether this effectiveness of road salt can be linked to the full range of roads throughout our transportation system, the Salt Institute supported a major study that encompassed the broadest possible range of roads and winter conditions. The study was carried out by the University of Waterloo using the Ontario Ministry of Transport’s huge database representing more than 1800 km of roads over seven winter seasons.
Five types of data were obtained and compiled, including weather, traffic, collision, road surface conditions and winter operations data. Although traffic accidents are the result of many factors, this study made it clear that road surface condition was by far the single most important factor in determining the number and severity of accidents during the winter season. Other factors such as invisibility, precipitation intensity, air temperature, wind speed and miles traveled were important, they paled in comparison to the impact of road surface condition. And that is the reason why the effective application of road salt to dramatically improve road surfaces is so critical in reducing accidents.
The before and after snow event analysis on four-lane highways showed:
- A 93% reduction in accidents.
- A 42% reduction in accidents on smaller 2-lane roads.
This difference is due to the ability of heavier traffic volumes to effectively distribute the applied salt more rapidly.
What is critical is that this enormous study confirms the previous Darmstadt and Marquette university studies and quantitatively demonstrates the critical importance of road salting on bringing safety and mobility to all types of roads in winter.
Battling snow and ice comes with a price tag, of course, but the study’s cost-benefit analysis shows it is well worth the investment. Deicing pays for itself a mere 25 minutes after salt is spread.
Statistics kept by the Federal Highway Administration help illustrate the prevalence and danger of snowy, icy roads:
- Over 70 percent of the nation’s roads are located in snowy regions, those which receive more than five inches average snowfall annually.
- Nearly 70 percent of the U.S. population lives in these snowy regions.
- Over 1,300 people are killed and more than 116,800 people are injured in vehicle crashes on snowy, slushy or icy pavement annually.
- Every year, nearly 900 people are killed and nearly 76,000 people are injured in vehicle crashes during snowfall or sleet.
- Each year, 24 percent of weather-related vehicle crashes occur on snowy, slushy or icy pavement and 15 percent happen during snowfall or sleet.
- Freeway speeds are reduced by 3 to 13 percent in light snow and by 5 to 40 percent in heavy snow.
- Average speeds on arterial roads decline by 30 to 40 percent on snowy or slushy pavement.
- Winter road maintenance accounts for roughly 20 percent of state Department of Transportation maintenance budgets.