Crews always attempt to clear these routes before rush hour. Occasionally, snow storms will hit just as rush hour is beginning which causes delays for both plowing crews and traffic. Streets are divided into four priority levels based on traffic volume, posted speed limits and potential safety concerns. Main thoroughfares, classified as Arterials , are always plowed first. This creates a channel in the snow for motorists to access connecting through streets earlier in a storm.
Crews return later to finish clearing the snow.
Today, Naperville has more than 1,000 Priority Three streets, compared to about 350 such streets just a few years ago. First, the City uses anti-icing units that apply a salt solution to major thoroughfares in advance of a storm. When either snow or ice begins to accumulate, rock salt is spread on streets to prevent unsafe travel conditions. The amount of salt used is based on total accumulation, temperature and traffic conditions. Rock salt is pre-wetted with either a rock salt brine solution or liquid calcium chloride to accelerate melting.