DOTs Work to Improve Winter Highway Safety, Efficiency, and Service
Winter Highway Maintenance Innovations: From New Technology to Beet Juice, Safety Lights, Equipment, and Storage, DOTs Work to Make the Most of Their Resources
With winter storms arriving as early as October and often returning through March, snow and ice removal consumes significant resources at the Departments of Transportation in Iowa, Kansas, Missouri, and Nebraska.
“We start prepping for winter operations as soon as the previous winter is done,” said Jeni Campana, Communications Division Services Manager for the Nebraska Department of Transportation (NDOT). “We get equipment and supplies ready to go, then spend a lot of the summer and fall, on top of normal maintenance activities, making sure new employees are comfortable with our snowplow trucks.”
Each year, the DOTs work to improve safety and efficiency on their highways. Since salt remains so cost-effective, it has been a long-time staple in winter maintenance efforts. However, mixing the salt with water (called salt brine) can improve results in certain circumstances.
“Our most effective strategy is to monitor forecasts and get out in front of the storms by pretreating with salt brine before the snow starts to fall,” said Laurie Arellano, Director of Communications for the Kansas Department of Transportation (KDOT). “Putting material under the snow and ice is known as anti-icing; trying to melt snow and ice from the top down is known as de-icing and takes more time and material to clear the roads.”
The Iowa DOT uses the brine to increase the effectiveness of its salt supply. “All of our solid material is pre-wet with salt brine at the spinner/spreader before it’s applied to the roadway, which helps reduce the amount of bounce and scatter,” said Craig Bargfrede, Winter Operations Administrator.
The Missouri Department of Transportation (MoDOT) combines salt brine with “beet juice,” an agricultural by-product, to treat bridge decks in advance of storms. “Rather than a chloride, beet juice has an alcohol that performs the de-icing, and it also has a stickiness that helps keep the brine on the road,” said Todd Miller, Maintenance Liaison Engineer.
In Kansas, “We started using the agricultural by-product about three years ago as an additive to our salt brine, and its use continues to spread across the state,” Arellano said. “Beet juice has been shown to prevent ice crystals from forming, and that helps with the removal of snow and ice from the road.”
In addition to these common strategies, each state continues to look at new materials, technologies, and approaches to improve winter maintenance.
Iowa: Safety Lighting and Snow Fences
This winter, the Iowa DOT is expanding the use of a special lighting package to increase safety. All of the state’s snowplow trucks are being outfitted with alternating blue and white lights on the rear, in addition to an existing, 360-degree rotating amber light on top.
“During the 2016 Legislative session, the Iowa DOT was granted approval to conduct a three-year pilot with our Central Iowa District,” Bargfrede explained. In the first two years of the program, “We saw a decrease in the total number of rear-end or side-swipe crashes, and a huge increase in the number of hours of operation between either rear-end or side-swipe crashes in the Central Iowa District.”
Given those results, the state legislature passed a bill that eliminated the third year of the pilot study and allowed the DOT to add the new lights to snowplow trucks statewide. “If a motorist sees flashing blue-white-amber lights, they need to realize they’re approaching an Iowa DOT snowplow traveling at an average speed of 25 to 35 miles per hour,” Bargfrede said.
In addition to the lighting package, “All 900-plus trucks are outfitted with GPS/Automatic Vehicle Locator (AVL) systems, along with IP cameras that take forward-facing pictures every five minutes from the operator’s perspective,” Bargfrede said. “These tools give us the ability to manage our winter operations resources, track our material usage, monitor what’s happening on the system, and provide timely travel information to the public via our 511 and Track a Plow websites.”
A statewide salt dashboard factors in detailed weather information to produce an expected salt and labor use for each area, each day. “This information has identified potential problem areas in a timely fashion and helped us reduce salt usage across the state without reducing service levels,” Bargfrede said.
In the field, a cooperative snow fence program reduces blowing and drifting snow on the roadway, increasing safety and lowering snow removal costs. During the 2017-2018 winter season, the Iowa DOT signed agreements with over 200 landowners. “These agreements are a combination of permanent snow fence, standing corn, and standing round bales that totaled just under 75 miles of snow fence,” Bargfrede said.
Kansas: Upgraded Equipment and Training
In Kansas, “Our weather patterns, even within the same storm, are very diverse,” Arellano said. “We bump up to Colorado in the west so that area gets more winter weather. Our districts in the southern part of the state, particularly the southwest corner, get very little winter weather. Because of the variance, each DOT district determines the most effective treatment for their conditions.”
To plan and schedule crews for approaching storms, “We utilize a Road Weather Information System (RWIS) and a custom forecasting service,” Arellano said. “KDOT operates 41 RWIS stations that provide both atmospheric conditions and pavement temperatures, and we also utilize RWIS sites maintained by the Kansas Turnpike Authority.”
Regular upgrades maximize winter equipment performance. Through the years, KDOT gradually replaced single-axle trucks, which hauled five tons of material, with larger and more powerful tandem-axle trucks that haul 10 to 12 tons. Recently, “We started purchasing material spreaders that have augers rather than a conveyor system to produce a more uniform spread pattern,” Arellano said.
However, “Our greatest challenge is always the number of new equipment operators,” Arellano said. “To help get new drivers ready, we developed a two- to three-day training class with classroom time, hands-on work in and around the dump trucks, and a focus on safety.”
Missouri: Magnesium Chloride and Market Adjustments
In addition to plow trucks, MoDOT uses more than 80 tow plows (a trailer-mounted plow that clears two lanes in one pass) to clear its highways – a much higher number than in surrounding states. Just call Missouri the home of the tow plow.
“Bob Lannert, who was in charge of winter operations before me, designed the tow plow,” Miller said. “Bob retired from MoDOT and patented it in 2007.”
Innovation continues as MoDOT incorporates magnesium chloride into winter treatments. “In some of our urban areas where we want to go as far as we can with our salt and stay away from abrasives, we’ve pretreated some of the salt with magnesium chloride,” Miller explained. “The magnesium chloride drops the temperature down to where the salt can treat the road. It also includes a corrosion inhibitor.”
This winter, St. Louis is treating their entire salt supply with six gallons of liquid magnesium chloride per ton, while the Northwest District and the Springfield, Missouri, area will try the process for the first time.
After encountering problems with fuel last year during extended periods of subzero temperatures, “This year we’re being a little more aggressive in making sure we get all of our tanks cleaned out and then, as new fuel comes in, we’re testing before it gets unloaded into our tanks to ensure it contains all the right additives for our winter fuel mix,” Miller said.
MoDOT also made a change designed to fill their personnel needs. “We’ve had issues recruiting enough people to provide the response we want with over 1,500 plow trucks,” Miller said. “To combat that, we’re offering a market adjustment of $3 per hour for our winter response team.”
Nebraska: Technology and Research Initiatives
Nebraska uses an AVL system to track its snow fleet. “That allows us to tell where our trucks are, and they have real-time, in-cab information to see the road temperature and what the weather is doing so they can determine the best use of materials at the time,” Campana said.
Later this winter, NDOT hopes to expand communication efforts by making the Track a Plow application available to citizens. “There’s been positive feedback from the public in states that use the technology, so we’re hopeful it will be another piece of transparency we can provide,” Campana said. “We’re piloting it now and ironing out the final details.”
In the northeast part of the state, NDOT’s District 3 just started using a 200,000-gallon, glass-fused-to-steel storage tank for liquid de-icers. “Most of our other districts have much smaller tanks of only 10,000 to 20,000 gallons,” Campana said. “We’re trying out this very large tank to see how it works.”
To increase efficiency going forward, “Nebraska is leading a national research project designed to improve evaluation metrics and scoring criteria on buying winter maintenance materials,” Campana said. The study is part of the Clear Roads program, which brings together transportation professionals from snow states.
“Winter maintenance materials are expensive, so we want to make sure we use them effectively and in a cost-effective manner so we can keep our high satisfaction rating with the public, but also be good stewards of the public money we use,” Campana explained. “If we get good information from this research, other states can use it in their winter operations to be as cost-effective as possible.”
Winter Facts by State
- Lane miles under Iowa DOT responsibility: 24,243
- Equipment: 902 snow removal trucks; 45 motor graders; 133 end loaders; 11 heavy-duty, self-propelled snow blowers; 30 snow blower attachments for loaders and 61 for tractors; 22 tow plows
- Personnel: 1,200 snowplow operators, mechanics, and supervisors at 110 maintenance garages
- Salt storage capacity: 222,185 tons
- Annual materials use (five-year average): 121,454 tons of rock salt; 21.78 million gallons of salt brine; 39,371 gallons of liquid calcium chloride; 963 tons of calcium chloride flakes; 11,210 tons of sand
- Average annual cost of winter maintenance: $65 million
- Lane miles under KDOT responsibility: 25,000
- Equipment: 591 dump trucks equipped with a front plow and material spreader, many with wing plows; seven tow plows; a fleet of motor graders, loaders, and other support equipment
- Personnel: 1,200 snowplow operators
- Salt and sand storage capacity: 200,000 tons in 326 storage buildings and bunkers
- Average annual materials use: 16,000 tons of salt, 3.5 million gallons of salt brine, and 17,000 gallons of magnesium chloride
- Annual cost of winter maintenance: $14.5 million in 2017-2018; ranged from $8 to $22 million in last five years
- Lane miles under MoDOT responsibility: 77,570
- Equipment: 1,500 plow trucks and 80 tow plows
- Personnel: 3,400 permanent and part-time plow truck operators
- Salt storage capacity: Over 200,000 tons
- Average annual materials use: 140,000 tons of salt, 3 million gallons of salt brine, and 700,000 gallons of beet juice
- Annual cost of winter maintenance: $40 million in 2017-2018; five-year average $44 million
- Lane miles under NDOT responsibility: 23,000
- Equipment: 700 plow trucks and 30 tow plows
- Personnel: 1,100 field employees
- Number of salt stockpiles: 130
- Average annual materials use: 120,000 tons of salt; each district produces their own salt brine
- Average annual cost of winter maintenance materials: $14 million