Safer Winter Maintenance

Increasing equipment visibility and protection
 means safer winter operations.

by Ruth W. Stidger, Editor-in-Chief

Both motorists and equipment operators need the safest possible atmosphere during winter road maintenance.

Blowing snow, sleet, or freezing rain decreases visibility of a snow plow ahead in addition to providing drivers with slick road surfaces.

While guidelines for fixed work zones are well established guidance for a moving work zone, such as snow removal or ice control, is less clear.

The Iowa State University Center for Transportation and Education conducted two surveys to determine what departments of transportation are currently using in their moving work zones.

Lighter and brighter equipment colors provide the basis for most states’ protective measures, says Ali Kamyab, principal investigator for the CTRE surveys.

Reflective materials, amber-colored lights, and orange-colored vehicles are most commonly used.

Additional warning lights, shadow vehicles, and truck-mounted attenuators also help, Kamyab says.

Retroreflective strips

The Texas Transportation Institute conducted a study on the effectiveness of retroreflective magnetic strips on Texas Department of Transportation work vehicles.

The 8-inch-wide orange and fluorescent-orange magnetic strip was applied to flagger vehicles. The study determined that the strips have an insignificant impact during the daytime, but could improve the visibility of vehicles during nighttime or low-visibility winter weather.

Advanced vehicle control

Advanced vehicle control systems reduce risk to both equipment operators and motorists at work areas, according to Kamyab. These systems have been applied to shadow vehicles and to snow-removal trucks.

During snow blowout conditions, snow plow operators sometimes have to guess where the edge of the roadway is, which can lead to damage. The systems could be used to provide the operator with help by either making a fully automatic steer control similar to cruise control, edge-of-the road warning systems, and forward collision warning systems. The advanced vehicle control systems may also let the driver work at a higher speed and more efficiently in a safe environment.

The advanced vehicle control systems on snow plows would operate by using a magnetic guide path in the road, Kamyab says.

The Advanced Highway Maintenance and Construction Technology Center developed the Advanced Snowplow to help operators remove snow more efficiently and safely. This plow includes a lane-position indicator, lane departure warning, and collision warning system.

The plow was field tested on parts of Interstate 80 in California and U.S. 180 in Arizona where snow removal operations are very difficult during the winter. The study sites were mounted with magnetic marker systems, used by the lane-position indicator, and the lane departure warning system. The study concluded that use of the plow could lead to better safety and efficiency.

Snow plow visibility

In a good part of the United States, snow and ice control are the most hazardous jobs for maintenance crews. Snow plowing becomes so dangerous because of the reduction of visibility from blowing snow, reflected headlight glare, and obscured windows the CTRE study found.

A National Cooperative Highway Research Program study investigated methods to improve visibility for the snow plow’s operator and the vehicle itself. The study concluded that steady-burning light bars, mounted along the rear edges of the snow plow will improve vehicle drivers’ ability to detect changes in the plow’s speed and will provide an indication of its width.

The study also indicated that the use of side vanes with a 20-degree angle on the rear of the plow reduces snow accumulation letting vehicle drivers see plow rear lighting more effectively.

The study also included an investigation of different applications that can be applied to snow plows to increase visibility and safety.

illustration by Edd Hickingbottom

Front plows with deflectors, with a trap angle of about 50 degrees, reduce the amount of debris blown onto the windshield. Packing flaps at the discharge end of front plows also reduce the size of snow cloud around the plow. Mounting narrow-beam lights as far from the operator’s line of sight as possible reduces the glare. Narrow-beam lights should be placed on the passenger side of the plows.

In Iowa, the Department of Transportation conducted a study to investigate crashes involving the departments snow plows. they found that the rear end of the plows need to be more visible to give approaching vehicle drivers more time to respond.

They mounted a set of diverging lights on the rear of the box as a solution. They also used rear deflectors to reduce the amount of airborne snow and snow accumulation on the back of the trucks.

Reflective tape was applied to the upper side of dump boxes, tailgates, and cab protectors.

Four years after the initial study, the department conducted a second study to find out whether the recommended strategies were working. After completion, researchers suggested that older plows be equipped with deflectors. Designs of newer plows had them built in.

The researchers also recommended use of SPI Industries’ scoop tailgate deflectors on all new trucks, as well as current fleet trucks, to decrease the amount of snow accumulation on the backs of the vehicles.

To improve the visibility of the taillights, crews in the Ames, Iowa maintenance shop designed and built taillight air blasters. A blast of air, controlled by the plow operator, removes snow buildup on the taillights. It costs about $120 to install the device.

The Iowa DOT also experimented with making the rear of snow removal vehicles more visible by placing reflective tape on orange safety fence mounted on the tailgates of the snow removal vehicles.

The fence blows in the wind as the vehicle travels, not allowing as much snow to accumulate onto the reflective tape and making the vehicle more visible from behind.

The department recommends future evaluation of rearview cameras and dual-speed displays on interstate trucks. Rearview cameras let snow plow operators view approaching vehicles. The dual-speed displays on the plow tailgates are set off by an approaching vehicle, showing the operator his or her plow’s speed and the speed of the approaching vehicle.

Now in use

The Center for Transportation Research and Education contacted 48 state departments of transportation and several Wisconsin counties to look at current winter practices, Kamyab says.

Wisconsin counties were included because the state’s policy allows roadway maintenance contracting to local counties. Thirty-four state DOTs and three Wisconsin counties responded to the survey.

Visibility of snow removal vehicles is generally improved by using warning lights, reflective tape, and other devices. Most state agencies apply more warning lights on their snow-removal trucks than on standard ones, according to survey returns.

More lights are placed either on the front cab or on the vehicle’s rear.

Vermont places rear-facing lights in the rear body corner posts, along with two large strobes mounted on swinging plates on the tailgate.

Iowa snow plow trucks use a dual amber rotating beacon and two amber rear-directional alternate flashing strobes, Kamyab says.

Alaska, Colorado, and Vermont have placed warning lights on the end of the wing plow.

Placing different colors of warning lights than normal is another method used. Arizona and Colorado use blue warning lights, along with amber lights, on snow-removal vehicles.

Minnesota and Nebraska use white warning lights on their snow plow trucks. The white lights are mainly used during daytime conditions. Minnesota applies white-colored lights to the rear of the box on all trucks with left-side wing plows.

LED lights are mounted on some states’ snow plow vehicles. Idaho uses LED taillights on all snow plow trucks.

Vermont and Colorado place LED warning lights on the end of the wing plow.

New Hampshire mounts small strobe lights on the extension arms of the mirrors on some of their snow plows.

Some states use more reflective tape when a vehicle is used for snow removal. Alaska and Minnesota place reflective tape on wing plows.

Iowa has experimented with applying reflective tape to safety fence on the back of snow plow trucks.

Another commonly used device on snow plow trucks is a deflector, Kamyab says. Many states use some form of a deflector on the front plow to reduce the amount of airborne snow and splash-back onto the truck’s windows. Some deflectors consist of a rubber strip hanging down in front of the plow. Others extend from the discharge end and then hang down.

New York even uses a standard bug shield to prevent snow splash up on the truck’s windshield.

Less commonly used deflectors include airfoils, also known as rear or tailgate deflectors. These cut the amount of airborne snow from behind and reduce the amount of snow that accumulates on the rear of the vehicle. Alaska, Idaho, and New York are among the states that use airfoils on their snow plows.

Another tactic reported by the states is to place orange flags on plows to make them more visible. Kentucky and Nevada use the flags.

Missouri and Nebraska commonly use snow deflectors.

County plows

Another CTRE survey was headed by Ali Kamyab, along with Tom McDonald as principle contributor and Brandon Storm as research assistant.

This team contacted all 99 Iowa counties, surveying maintenance equipment visibility strategies in snow removal and other operations.

Of 61 responses, 46 counties use reflective tapes on their snow-removal vehicles. Of these, 19 counties apply reflective tape to the plows.

Fifty-one counties mount warning flags on the vehicles and/or plows.

Another common device used is auxiliary headlamps. Forty-three counties use these above the front plow, either mounted on the plow frame or onto the vehicle itself.

Twenty-four counties use snow plow deflectors.

The most commonly used type of warning light is strobe lights.

This survey shows that most counties use similar traffic control and warning devices during snow-removal operations. 

Snow Removal Devices Used for Safety

State and Snow removal device use

Alaska - On grader and truck wing tips, install strobe lights. Use conspicuity tape on some wing plows depending on location. Rural locations are one-lane operations and don’t have problems with motorists trying to pass on the right. Dump boxes are equipped with strobe lights and deflectors to decrease snow accumulation.

Arizona - Snow plows use amber strobe lights on the front. Have strobe lights on all four corners placed on the bumper. Have blue and amber strobes on the back. Use snow plow deflectors and tailgate deflectors.

Arkansas - Use snow plow deflectors.

California - Apply work lights on the wing plow. May apply one or more one-way flashing lights at the corners of the dump box.

Colorado - Use the Whelen snow and fog lights on snow-removal vehicles. Snow-removal vehicles also run a combination of amber and blue lights. Snow plows have strobes on the left- and right-hand side of the cab. Place strobes on the corner posts of the bed on the rear, so snow plow has a total of four strobes. Place an LED warning light on the end of the wing plow.

Connecticut - Snow plows are J-style. Some drivers opt to add deflectors.

Georgia - Use snow plow deflectors. Have lights above the snow plow.

Idaho- Snow plows have a Whelen Superstrobe Comet Flash light mounted on the truck cab. At the top/center rear of the sander is a dual rotating halogen light. Each truck is equipped with four amber halogen lights on the side of the sander, two per side. These lights are equipped with a flasher unit to give the appearance of a bouncing ball with lights flashing side-to-side and top-to-bottom. All snow plow trucks have LED taillights. Dump bodies have four total and sanders have four total lights. If a truck has a slide-in sander, the vehicles could have as many as eight taillights. Use an air foil on theback of all sander bodies. Airfoil scoops air coming over the top of the sander and directs it over the back of the sander to keep rear lights visible.

Illinois  - Has done some experiments on snow deflectors, but not in general use.

Iowa - Use snow plow deflectors on some plows. New plows being used do not require a deflector. Some snow plows use tail light air blasters. Experimenting with continuity tape placed on orange safety fence on the rear of the vehicle. Snow plow trucks use a dual amber rotating beacon and two amber rear-directional alternate-flashing strobes.

Kentucky - Snow plow vehicles have lights on tailgate corners and on the cab. Place flags on the plow, use snow plow deflectors, and place lights above the plow.

Maine - Run more lights on snow plows than normal maintenance vehicles.

Minnesota - Snow plows are equipped with six amber strobes. Four of these are mounted in two housings on top of the stationary cab shield. The other two are mounted on the top rear of the dump box. In addition, put two white strobes on the rear of the box on all left-hand wing trucks. Districts have the option of adding white strobes to other plow trucks. White strobes are used only during daylight hours. Other vehicles use a double rotating or strobe light; either amber or blue. Trying a few LED lights. Put reflective tape on wing plows and on the underbody.

Missouri - Commonly use snow deflectors.

Nebraska - Use some snow plow deflectors. White and amber warning lights are mainly used during snow removal.

Nevada - Place orange flags on the rear of snow plow vehicles.

New Hampshire - Some snow plows have small strobes mounted on the extension arms of the mirrors. Also mount some lights on the back side near the tail gate.

New York - Most plows have snow deflectors. Some have deflectors that extend out, then down. Some snow plow vehicles use standard bug shields to prevent splash-up on the windshield. Some vehicles have airfoils on the back of vehicles to prevent accumulation of snow on the rear of the vehicle.

North Carolina - On snow plow vehicles, use the standard lighting of two high-intensity strobe lights mounted on each side of the cab protector. Also place a yellow strobe mounted on the rear of the in-body material spreaders. Some trucks are equipped with only a tailgate spreader and will have no additional light other than standard on the dump truck. Every tailgate on the dump bodies are striped with reflective, glass-beaded paint.

Ohio- Snow plows are ordered in gloss black. Attach 18-inch orange plastic tubes to the outside edge of the moldboard so the drivers can see plow placement.

Oklahoma - Use snow plow deflectors.

Pennsylvania - Use snow plow deflectors.

Vermont - Use snow plow deflectors. Snow plow trucks have a 360-degree light mounted either on a bar on top of the cab or on the upper mirror brackets so there is a light on each side. There are rear-facing lights in the rear body corner posts. Two large strobes are mounted on swinging plates on the tailgate so they aim directly back whether the body is up or down. Experimenting with LEDs mounted on the discharge end of the wing plow.

Virginia - During snow removal, an auxiliary snow-removal headlight with park/turn lamps is used. Use clear halogen head lamp and amber park/turn lamps mounted in the grill or fender. Use spreader light mounted under the left rear corner of the dump body, facing down.

Reprinted from Better Roads Magazine
October 2003

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