The spreading of salt and abrasives is one of the biggest challenges when it comes to snow clearing. It has to be continuously assessed based on the temperature of the road and the amount of snow on the ground.

Salt is used in the winter to melt the snow and ice in sub-zero temperatures. Its impact is limited in extreme cold weather. The temperature to watch is that of the road, not of the air, as it changes more slowly. The colder the road, the longer it takes the salt to act.

Salt works as long as the road temperature is above -5°C. Below that, its effectiveness gradually diminishes as it falls closer to -10°C, and often has to be combined with gravel to give vehicles any traction. 

The key to effective and responsible spreading is to determine the right amount, the right location and the right time.

In case of heavy snow falls, there is no advantage to spreading salt before clearing. Under those conditions, the salt gets too diluted and loses its effectiveness. During snow clearing operations, crews will still spread some salt because the spreaders have front and side blades that scratch the snow before they spread the salt. After that, once the precipitation stops, more salt is spread if it is not too cold and the snow has been completely cleared off the roads.