At times, road conditions warrant the use of sand, but can actually make driving conditions more hazardous later. During and after a weather event, sand, wind, and increased traffic flow can exacerbate snow and ice buildup by packing it down to the point that a plow is no longer effective. This can be a very dangerous situation for traffic. The highway department then has no choice but to use large equipment to remove snow and ice buildup to improve the condition of a road.
At times it is absolutely necessary to temporarily block intersections and roads for cleaning to ensure the safety of the public. These roads are only blocked or slowed for long enough to get them cleared. It is always a good idea to allow extra time when travelling so that you can adjust for changing road conditions and cleanup efforts after an event.