Salt Or Sand: What Impacts Plow Truck Decisions?

In a winter where we've seen pretty messy driving conditions - a question often comes up:  Why do the plow trucks sometimes use sand and sometimes use salt when treating the roadways.  The answer has a lot to do with science and temperature conditions.

According to a graphic posted on the MNDOT Facebook page, there are very specific reasons for using salt or sand.  Salt is often used when the temperatures are lower and to keep collecting snow "workable".  Meanwhile, sand is the choice when temperatures get cold (as salt stops being effective the colder it gets) and at intersections and ramps - where traction is important.