A resource for winter maintenance decision makers
Although other chemical combinations and alternatives have been explored in recent years, rock salt remains the most proven-effective, cost-efficient solution for clearing roads of snow and ice. According to the American Highway Users Alliance in Washington, DC in 2015, road salt reduces crashes by up to 88% and injuries by up to 85%.
Safer roads and fewer accidents also mean fewer complaints from taxpayers, as nothing prompts an angry phone call to City Hall or the DOT faster than a road that hasn’t been cleared quickly or thoroughly enough.
The answer is “no,” assuming we are using the latest smart salt spreading technologies.
In fact, with smart salt spreading technology, salt usage could be reduced by as much as 35% (or 7.7 million tons) while, at the same time, actually improving road safety and minimizing environmental impact. So it’s not necessary to literally see salt caked on the road to know it’s working.
Dry salt or salt that is not thoroughly pre-wet at a sufficient ratio takes longer to melt ice and is more likely to bounce or be blown off to the side of the road where it does not improve safety. According to the Michigan Department of Transportation 2012 Bounce and Scatter Study, pre-wetting keeps 30% more salt on the intended surface where it does the most good.
Salt works by lowering the freezing temperature of water. It becomes a more effective deicing agent when it has moisture which jumpstarts the melting process and facilitates adhesion.
In European countries with significant snowfall, field studies have shown that the higher the ratio of liquid pre-wet to granular salt, the faster the ice melts with an optimum ratio defined as 70:30 granular to liquid pre-wet ratio. (Most municipalities in the US currently only use a 5% pre-wetting ratio.) With a sufficient pre-wet ratio, effective melting begins in as little as 10 minutes.
This super-saturated mixture not only works faster and stays on the road better (without bouncing or blowing off), but it also reduces salt usage. According to the Clear Roads National Research Consortium, pre-wetting rock salt at an optimal ratio provides 20% - 35% material savings.
Some smart spreaders can cover up to three lanes at the same time—a feature that not only provides safe conditions faster but also more cost efficiently by reducing labor time and fuel costs.
Yes. With advanced automated controls to monitor ground speed, air and ground temperature, and accurate lane placement, drivers can focus all their attention on driving without distractions in treacherous conditions. Intuitive, easy-to-use controls also shorten learning time—another major advantage given today’s tight job market and shortage of experienced drivers.
Absolutely. When excess salt on roads washes away, it steadily accumulates in rivers and streams, preventing oxygen from reaching the bottom layers of the water and killing off plants and aquatic life. According to the US Geological Survey, an estimated 40% of the nation’s urban streams have chloride levels that endanger their aquatic life, largely because of road salt.
Trees, plants and grass on the side of the road also suffer, as excessive road salt dehydrates them and makes it difficult for them to absorb water. The result is leaf damage, stunted plant growth and falling leaves or needles. And even small quantities of rock salt have proven toxic for birds.
Less salt means less harm to water sources, vegetation and wildlife.
Beyond safety, lower costs and less environmental impact, smart salt spreading technology can help optimize fleet performance. Advanced telematics available on many smart spreaders allow municipalities to efficiently plan routes and monitor equipment performance to keep spreaders running at peak levels.
Vehicles equipped with a GPS tracking system and data controller can transfer data wirelessly to a central server that allows for live monitoring of winter service operations. Fleet management software can program the most efficient and consistent routes and allow department heads to always know where their trucks are and how efficiently they are operating.