Not so much of a speed trap as well patrolled. Officers patrol 21 both directions and will issue citations. I drive the length of 21 through Caldwell several times a week. Police presence is there, but I haven’t really noticed any officers hiding in sneaky spots waiting to pick off offenders. The speed limit drops from 70 to 55 to 45 and finally to 35. They will ticket you if you fly through town, but in 7 years I don’t recall ever seeing an officer sitting next to a decreasing speed sign and rubbing his hands in anticipation.