TROY, Mo. (KSDK) – Both the Missouri and Illinois Departments of Transportation have been proactive over the past few days, pre-treating roads and bridges in anticipation for a winter storm expected to sweep the bi-state area Wednesday night.

IDOT has been out in full force, salting the district's northern-most counties: Greene, Calhoun and Jersey.

MoDOT called everyone in at 3 p.m. Wednesday, and are fully staffed with 200 trucks out in the streets.

What makes the storm unique is a huge temperature swing, with mild temperatures earlier in the day that quickly dropped come nightfall.

Because of the drop, MoDOT says it will most likely use some additives to the salt like beet juice. When it gets really cold, they mix in calcium chloride, which helps the salt work in frigid temperatures.