Good Winter Maintenance Boosts Road Safety

Anti-iced, deiced, or otherwise cleared roads make most drivers feel safe as they travel.

by Ruth W. Stidger, Editor-in-Chief

A survey by the Canada Safety Council underlines the importance of cleared roads to drivers.

The poll, conducted by Decima, found that 46% of drivers said cleared roads were the most important factor in safe winter driving, rating the item 10 on a scale of one to 10. The average rating of all survey respondents for cleared roads was 8.4.

Almost as many — 44% — said the quality of winter maintenance on the roads they most often use rates a 10. The average rating of all respondents was 6.9.

Roads should be plowed, clear, and deiced, respondents concluded.

The driver factor

Drivers lack the defensive skills needed to handle ice or snow-covered roads, according to Emile Thorien, president of the CSC. Driver behavior contributes to about 85% of all collisions and related injuries, the council reports.

In the U.S., an earlier study from Marquette University in Milwaukee found that collisions were up to eight times more frequent before deicing than after.

Anti-icing

While more conventional snow removal such as plowing and salting plays a role in good winter maintenance, anti-icing has moved to the forefront of the way most states and many local agencies plan to handle snow and ice control.

A survey sponsored by the members of the Strategic Highway Research Program’s Anti-icing/RWIS Lead States Team found that:

1. Reported use of anti-icing strategies rose from 79 to 90% when comparing 1997 and 1999.

2. The proportion of states with rate application guidelines went from 43 to 60%.

3. States making anti-icing training available doubled, from 27 to 57%.

4. A majority — 86% — plan to expand or start anti-icing.

5. Sodium chloride and magnesium chloride are still the most-used anti-icing chemicals.

6. Hydraulic pumps are being used more often than electric pumps for chemical application.

7. Bulk tanks continue to be the main method of chemical storage.

8. The proportion of DOT vehicles equipped for anti-icing rose from one-in-10 to one-in-five.

9. Lane miles treated with anti-icing strategies jumped 50%.

10. About 25% of all maintained lane miles were treated with anti-icing.

RWIS’ role

About three-fourths of the states responding use Road Weather Information Systems to help determine the need for anti-icing. Of these, 96.7% use from one to 75 RWIS tower sites.

All of the states use embedded pavement sensors.

Most of the states — 80% — use short-term weather forecasting, while 53.3% use visual surveillance equipment and 13.3% use thermal mapping.

In Canada, anti-icing was less popular, with half of the 10 provinces responding reporting they use the strategies.

Two of the provinces — 20% — report that application rate guidelines or specifications have been established for anti-icing or that they offer anti-icing training.

Four of the 10 provinces plan to expand anti-icing efforts.

Of the provinces using anti-icing, 2.3% of their total lane miles are being treated with the strategies. Most use sodium chloride, with 20% reporting magnesium chloride use.

Anti-ice Once or Twice a Season?

Russ Alger, director of Michigan Technological University's Institute of Snow Research at the Keweenaw Research Center, may have found a way to cut winter maintenance costs while improving driver safety. 

Officially, it's known as Anti-icing Smart Overlays. From the top, a sample looks like basic kitty litter."We're using a certain type of limestone now," says Alger, though researchers are working on other materials that will be even more efficient. The ground rock is stuck tight onto a small square of pavement material with epoxy. What this three-layer system does, Alger explains, is "soak up chemicals like a sponge." 

That's what makes Anti-icing Smart Overlays different. Typically, road commissions spread salt or other deicing compounds on roads to melt snow and ice. As ice melts, it washes the chemicals off, so the next time it snows, the trucks have to go out again.

But if the pavement were coated with an Anti-icing Smart Overlay, the salt or chemical wouldn't wash off. Stuck in the thin coating, it would be ready for the next snow, and the next. Theoretically, one application of chemical could last for weeks or even longer.

Alger doesn't envision resurfacing America's entire highway system, however. "At first the primary application would be bridge decks," he says. "It could eliminate the problem of ice on bridges, especially in western states, where they can be 100 miles from the county garage." 

What about when it really snows? 

"Light amounts of snow melt; with heavy amounts, it still accumulates but doesn't stick," Alger says, so it could easily be moved aside by a snow plow.

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