Maryland Roads on a Reduced- Salt Diet

The state has a new, more environmentally friendly way to fight snow and ice

     Now that winter has come to Maryland, the State Highway Administration is hard at work keeping our roads free of snow and ice. Snowplows are a familiar sight after a heavy snowfall. But just as much work goes on before the cold stuff even starts to fall. As soon as snow, sleet or freezing rain is forecast, fleets of trucks lay a preemptive layer of de-icers.
     Salt is the tried-and-true ingredient for fighting snow and ice on roadways. It’s effective, but it has its costs. The environment suffers from the increased salinity and from the byproducts of a fleet of diesel trucks spreading hundreds of tons of salt. There are also costs to our wallets, as our tax dollars buy the salt and equipment, the maintenance and labor to spread it.
      Targeting a 30 percent reduction in salt usage without compromising motorist safety, the Maryland State Highway Administration, along with most county and city departments, are developing new techniques to treat roads.
 
The Recipe
      You wouldn’t expect water to be the key ingredient to lessen salt. But use the right ratio of water to salt, and you save salt and the costs of depositing it. The perfect brine is 27 percent salt and 73 percent water.
     Historically, roads were treated with salt after snow started to fall. By then, snow and ice have bonded to the pavement. It takes more salt to break this bond than to prevent it. 
     Now when snow is forecast, special tanker-trucks with pumps and spray nozzles filled with salt brine move out to coat the roads. The snow and ice never bond to the road, so less total salt is required. The technique is called pre-wetting, with trucks spraying brine in a pattern of stripes, eight to 10 per lane at about a foot apart.
      Salt is still applied, but it, too, is pre-wet. Previously, dump trucks lost nearly 30 percent of salt off the road. No more. Now, traditional salt spreader trucks are being equipped with saddle tanks and nozzles. Water is sprayed on the salt as it exits the truck. Pre-wetting both hurries melting action and reduces salt “bounce and scatter.”
 
Spreading the Good News
      Five years ago nobody had heard of brine spraying.
      But after proving its effectiveness the last few winters, the State Highway Administration is now pre-treating all state highways. The Glen Burnie facility has four brine-spraying rigs; statewide there are 14. This winter 550 battle plows — 50 more than last year — are equipped with saddle tanks for pre-wetting salt. To support the fleet, the state has built 15 brine-mixing facilities, with 77 storage sites spread locally. Almost 1.4 million gallons — about 30 percent more than last year — of brine have been mixed and stockpiled. A mobile brine-making machine is being test-piloted in Garrett County. 
       County and local departments are following suit.
       “The Maryland State Highway Administration is committed to sensible salting and an overall salt usage reduction throughout the state,” says spokesman Charlie Gischlar. 
       Innovation continues. A new technique, called liquid-only, has graduated from a pilot program to mainstream. The former protocol pre-treats roads with brine before the storm and then spreads granular salt during or after the storm. In the liquid-only method, pre-treatment will be followed with more brine, no solid salt. 
      This year, each of the State Highway Administration’s seven districts has at least one liquid-only snow route. In Anne Arundel County, the routes include Rt. 10 between Rt. 2 (Richie Highway) and the Baltimore beltway, and parts of Rt. 176 (Dorsey Road). In Calvert County most of Route 2/4 will receive this treatment. To support this new technique, an additional 200,000 gallons of brine have been deployed across the state. 
 
Salt Per Mile Per Inch
      Measuring the effectiveness of these new techniques is difficult because every winter and every storm is different. Year-to-year changes in salt usage are mostly due to weather. The Highway Administration is seeking a better evaluation by tracking pounds of salt used per mile of road per inch of snow fallen. 
      Last winter was a pussycat. State expenditures on snow removal were half of the prior three years. Salt usage was barely 20 percent of that used for winter 2013-’14. My snow blower sat lonely and untouched in my garage all winter.
     This winter is already a different story. 
     Preliminary numbers are looking good. The 30 percent salt reduction goal is being met, costs are dropping and the environment is suffering less salt — with no loss in road safety. That’s good news — if only they could treat my driveway.