It’s posted at 30 mph the entire length from the factories all the way to Interstate I-265. It’s heavily patrolled by marked & unmarked county, city & state police. The County’s Prosecuting Attorney said “the Port owns the entire road” & ‘it’s to control the speed of the trucks going in & out of the Port’. Most state laws would describe the (3 miles est.) from “Middle Rd to the Interstate” be posted at 45 mph. In 9 years of using that road, I’ve never seen DOT (Truck Cops) patrol it. You can often follow the police exceeding the posted limit (without lights or siren) but be careful, they’re not opposed to stopping you for following them & exceeding the limit.