With more than 3,200 specially trained employees and hundreds of trucks that can be used to remove snow and ice across the state, the N.C. Department of Transportation works hard to prepare for winter weather and the hazards that come with it.
There are a lot of facets to winter weather readiness and response, and NCDOT is committed to making sure that they are all in place and work well together before winter comes.
Before, During and After a Storm
Maintenance crews across the state begin preparing for winter storms as early as fall by cleaning, repairing and testing equipment, reviewing snow removal routes and stocking up on necessary supplies, such as salt and sand.
When a storm is forecast for North Carolina, NCDOT relies on the National Weather Service to monitor conditions to stay ahead of the weather.
If conditions are good up to 48 hours prior to a storm, crews will pre-treat roadways with a salt-water mixture called brine to help keep ice from bonding to the pavement.
During and after a storm, crews in affected areas work around the clock to monitor changing weather conditions and treat roads. NCDOT has more than 1,900 trucks that can be equipped with plows and spreaders to remove snow and ice. If needed, NCDOT moves trucks and equipment from areas less affected by a storm to areas more affected.
After plowing roadways, crews use salt, sand – or a mixture of both – on road surfaces. Salt helps melt ice and snow, and sand provides extra traction.
NCDOT, which maintains the second largest state network in the country, is responsible for interstates, state and U.S. routes as well as secondary roads not maintained by area municipalities.
When it comes to clearing roadways, NCDOT's first priority is interstates and four-lane divided primary routes (N.C. and U.S. routes) that are essential to the movement of intrastate and regional traffic.
After these roads are clear, the priority moves to clearing lower-volume primary roads, high-volume secondary roads, lower-volume secondary roads and then subdivision streets.
Priority is based on the following criteria:
- Traffic volume
- Trucking routes and major business avenues
- Importance to hospitals and emergency routes
NCDOT crews have designated snow and ice removal routes that they must follow. Trucks traveling on roadways but not treating them are likely headed to their designated route.
NCDOT does not remove snow and ice from sidewalks, nor does it clear driveways. (Read more about the snow-clearing policy.)
General Statute 20-161 gives NCDOT and the North Carolina State Highway Patrol authority to legally remove abandoned vehicles from the shoulders of roadways and highways. In advance of, or during adverse weather, abandoned vehicles might be towed in an effort to facilitate maintenance operations and to make roads safer for drivers who might lose control of their vehicles. The quick clearance also prevents potential damage to abandoned vehicles that could possibly occur from maintenance operations (e.g., snow and ice being thrown against a vehicle) or the vehicle being struck by a passing motorist.
Vehicles off the roadway and not considered safety hazards are not immediately towed.
Drivers whose vehicles were abandoned within city limits can call their local police department. For vehicles abandoned outside city limits, drivers can contact the Highway Patrol at (919) 733-3861.
NCDOT owns and maintains a wide array of equipment to handle North Carolina winters. As of 2016, this includes:
- 1,739 dump trucks fitted with plows and salt/sand spreaders (attached when snow or ice is in the forecast)
- 495 front-end loaders and backhoes
- 332 motor graders
Pick-up trucks are also outfitted with snowplows to clear less-traveled roads when conditions merit. In addition, NCDOT works with local companies to use contract trucks and employees to supplement crews and equipment as needed.
NCDOT budgets $70 million annually for storm preparation and snow and ice removal across the state. Should NCDOT exceed that amount, additional funds are taken from emergency reserves.
Even if the budgeted amount is exceeded, NCDOT does not scale back its response, nor does it have fewer crews out clearing the roads. Crews continue to clear roads as quickly and efficiently as possible, whether it's the first storm of the winter weather season or the last.
NCDOT can store up to 170,000 tons of salt and sand and 1.52 million gallons of brine at its storage facilities in each of its 14 transportation divisions.
Brine – a solution made up of water and 23 percent salt – is used to pre-treat roadways in dry conditions when the temperature is above 18 degrees Fahrenheit.
The decision to pre-treat roads is made 24 to 48 hours before a storm, and brine must be applied when it is not raining. Rain dilutes solution and washes it off the road, making it ineffective.
Among a number of benefits, brine:
- Lowers the freezing temperature of water to about 18 degrees Fahrenheit (8 degrees below Celsius)
- Prevents snow and ice from bonding with the road's surface
- Keeps snow from being compacted by traffic, which can turn it into ice
- Is more effective and coats roadways better than plain salt or sand
- Gives crews time, since brining can occur up to 48 hours prior to a storm
- Costs 15 cents per gallon to produce. One mile of a single lane of road can be treated for about $6; rock salt costs about $14.38 to treat the same stretch of road.
Brine is made by loading a hopper with salt and water and agitating the ingredients until the solution is 23 percent salt. The solution is then pumped into a holding tank and loaded onto trucks to be sprayed on roads.
NCDOT crews will sometimes use a brine blend with 10 percent calcium to remove snow and ice during and after a winter weather event. This solution can be used in combination with rock salt when temperatures are lower to keep the salt working longer.
Salt and Sand
Crews use salt and sand to help clear roads when a storm hits. After plows clear as much snow as possible, a mixture is spread on roads, with special attention given to freeway ramps.
Salt works to melt the remaining snow and ice, and sand helps break up the ice and also adds extra traction to help vehicles stay on the road.
Driving in icy or snowy weather can be stressful and dangerous.
The result of melting ice and snow that refreezes into thin layers, black ice typically appears as wet spots on roadways. It is difficult to see and difficult to predict since it forms quickly. (Learn more about black ice.)
To treat black ice, NCDOT applies road salt, which lowers the freezing temperature of water, making it easier for ice to melt. Crews might also apply sand to help increase traction and break down the ice.
NCDOT does its best to treat areas it knows are prone to black ice, but often learns about it from law enforcement agencies and the public.
Most of the time, drivers can't see it until it is too late. The safest way to avoid black ice is to stay off roads unless you absolutely have to be out. If you do, drive slowly and leave plenty of space between vehicles in front of you.