Truck with a radar… not a radar detector

In my travels - I passed a truck that appeared to have a speed radar antenna (like what’s on the police car dash boards) mounted on an arm/support rod sticking off the tractor.

I had also read another forum where a driver of a bus had a speed detection device (Radar) that displayed speed of other vehicles.

Has anyone heard of this? What is the device used? Why-what is the point behind doing this?

 

Collision mitigation and adaptive cruise control.
Normally mounted in the front bumper.

 

Years ago the Canadian truck drivers started using a fish-finder to thwart a police radar. Some American drivers did that also, but didn't seem to catch on as much in the USA. I don't know if that would still work today. Maybe @AModelCat knows.

 

Not saying what this is, but it is well known in England that police use ordinary unmarked tractor units to detect lorry drivers using phones while driving or not wearing seatbelts thinking that they are too high up for cops in cars to see them.

 

Tennessee has been doing that for decades.

 

I know they have a state trooper rig or two but I've never seen one on the road, just parked at scales.

 

They use ride-along program where a trooper rides in the cab of a truck of a carrier.

 

I talked to one driver of SEFL, they do it all the time.

 

Traitors At least in England they have their own tractors to do the work......I think.

 

Texas had one also until it was stolen