These are large files that have been turned into road spikes, then hammered into the roadway pavement.
In Christian County, the Sheriffs Office found these inserted in the roadway today between Nixa and Highlandville.
They were inserted with length in conjunction with traffic direction, so visibility is slim. The first set was located on Aspen between White Ash and Harris. Another set was located on Aspen just south of Green Ash.