How do you determine in what order to plow roads?
Road Commissions organize snow plowing operations to service the most heavily traveled roadways first during and after a winter storm. Our first responsibility is to clear primary roads, and state highways. Typically, local roads and streets are among the last to be cleared. If the snow continues to fall or drift we may have to return to the state highways and primary roads before we are able to continue plowing local roads and streets. After those roads are passable, crews move on to clear local paved roads throughout the county. Typically, local subdivision streets and rural gravel roads are cleared after all other higher traffic roads within about two days after the storm. Although our crews may begin plowing/salting several hours before the morning peak traffic, and continue operations into the night, extended winter storms or continuing winds may require crews to continually plow the main high traffic roads and prevent them from reaching subdivision streets or rural gravel roads for several days.
Is it legal to pass a snowplow?
There are no state laws that prohibit passing a snowplow. However, the action of passing can be extremely dangerous because pavement conditions vary across the path taken to pass. Snowplows may be equipped with wing plow blades that can extend anywhere between 2 and 10 feet beyond the width of the truck. This wing plow blade is often not seen because of the snow cloud being kicked up by the snowplow. These wing plows can often weigh as much as a compact car.
A road commission truck pushed snow back into my driveway after I cleaned it out…
Throughout the winter months, our crews will be out clearing the roads during and after snowfalls. At the same time residents are clearing their driveways. Many times while this is going on, a snowplow truck will go by and fill in the end of a freshly cleared driveway with snow from the road, causing frustration and more clearing for residents. Please understand that the road commission’s first priority is the safety of the traveling public and clearing the roads of snow and ice and pushing it off of the road and shoulders, and sometimes into driveways, is a necessary wintertime evil. Residents sometimes call and ask why we cannot pick up the blade when going by their driveway. This is not a practical solution and our drivers would never finish clearing the roads due to the multitude of driveways. There is, however, a method of clearing your driveway that can help minimize the amount of snow (and frustration) during the winter months:
- If possible (not always practical), clear your driveway after we have finished plowing the roads
- When clearing your driveway, place as much snow as possible in the direction of travel, on the downstream side of the road.
- Clear an area upstream from your driveway opening to form a pocket for the snow from the road to go into. The result? More of the snow from the road will go into the pocket and less will wind up in the end of your driveway.(Click here for an illustration)
Why does the road commission push the snow off the road onto the shoulder, only to come back and push the snow farther back on the shoulder?
The road commission usually makes one pass to open the road up so that residents may get in and out. We then come back to widen the road, and then the shoulders for future snow accumulation.
Your plow truck knocked down my mailbox…
Since mailboxes are in the road right-of-way they are sometimes knocked down by road commission trucks when plowing snow or performing other road maintenance. Policies regarding the replacement of mailboxes and/or posts that have actually been hit by our equipment vary from county to county. If the mailbox or wooden post was broken off from the force of the snow coming off the plow blade, most road commissions will not replace or repair it. Please call your county road commission’s office for more information.
Why do bridges and overpasses freeze before the surface of the road?
Even while the temperature on the road surface is dropping, the heat underneath the road keeps it warm enough to prevent icing as temperatures drop below freezing. Bridges have no way to trap heat, so they continually lose heat and freeze shortly after temperatures hit the freezing point. The bottom line is that a bridge will follow the air temperature very closely. If the air temperature falls below freezing, a bridge’s surface will fall below freezing very quickly causing rain or snow to freeze and stick to the road surface.
Why can’t salt be put on roads and bridges before it snows?
Putting salt on road surfaces prior to a snowfall wastes time and money since salt often bounces from the dry road during application and, the portion that manages to land in the right location is subject to wind- which blows it off the road before it can do its job. Salt is most effective after snow has accumulated and the temperature is 20° Farenheit or higher. Under these conditions, the salt and snow will mix, melting snow into slush that can be plowed off the pavement. (This melting action will occur within two hours, less if traffic is using the highway.) If the temperature is below 20°F, the salt will have difficulty melting the snow and ice, so other methods are used. Abrasives are often put down for traction. Calcium chloride or other liquid treatments, including sugar beet based products, can be added to enhance the ability to melt the ice and snow. The road commission may change the mixture of salt and additives based on the ground temperature.
What is the importance of pavement and ground temperatures? Why not rely on just air temperature?
The ability of a deicing agent to melt snow and ice depends on the temperature of the roadway and not the air temperature. During the fall the pavement is often kept warmer than the surrounding air because of the warm soil. During the spring the reverse may be true. The pavement temperatures can be colder than the air because the soil is still frozen from the low winter temperatures. The sun also has a strong influence on the pavement temperatures. It can help heat the pavement and speed the melting process. Air and pavement temperatures can differ by as much as 20°F.
I’ve seen snowplows driving along during a storm with their plows raised. Why aren’t they plowing?
There are a couple of reasons plows aren’t always pushing snow. Plows may be in operation only to spread materials, or may be out of materials to spread and headed back to the garage to reload. Another possibility is that the driver does not have the responsibility for the road he is currently on, and is heading elsewhere. Plow routes are designed to minimize travel in between service areas. It is also possible that the road may have been treated with salt or de-icing products and plowing it may remove the mixture before it has an opportunity to work.
Why do workers spray liquid onto the roadways before a big storm arrives?
It may seem dangerous to add liquid to a road that might freeze, but the liquid is most likely calcium chloride or a beat juice mixture which will prevent snow from sticking to the road and prevent frost or black ice.
Why would salt be spread on a bare highway after a snowstorm is over?
The projected temperature of the road surface will impact the final treatment of a road. If plowing operations have finished and a road is left in “black and wet” condition, there is sometimes a danger of the water on the road re-freezing. There are times, especially at night, when this post storm salt application may be necessary.
Courtesy of the County Road Association of Michigan. www.micountyroads.org