That thing right before a Truck Stop

What is that thing suspended by a pole right before the truck stop. It always hovers over the far right lane and it looks like an RF transmitter of some kind? What’s it do? Why’s it there?

By “truck stop” do you mean the weighing and inspection station on interstates or do you mean the places to buy fuel and food?

If you’re talking about weigh stations, that was my father’s department in the Washington State Patrol. There are a couple of things it could be:

1 - It could be a gadget to check the height of truck’s loads. There are restrictions on how high a load can be. So on the approach to a weigh station, there will be a sensor mounted on a pole that will set off an alarm if the load is too high. When the alarm goes off, the driver is signaled to come into the weigh station and show that he has a permit for an over-height load.

2 - There is a new system in place in parts of the country that will allow a trucker to bypass the scales. The truck is equipped with a computer that stores the driver’s permit information and the weight of his load. The information is entered into the computer by the agency that sold the permits, usually the Department of Transportation. The load weight would also be entered the first time the truck entered the state with that specific load. I think it will also indicate if the truck is empty. This information is then broadcast via radio to the weigh station, enabling the truck to continue on its way without stopping at the weigh station. Saves everybody time.

I’d bet it is either a domed video camera, or an interface with vehicle mounted transponders such as EZ-Pass.

I’m referring to the weigh stations. It is not a camera. It could be a transponder thing. Or also one of those height checking radar things. I will try to find a picture.

If the OP is in California, I bet this is what he saw. All the weigh stations in my area have this system now.


It sounds like it is the new permit type system. I am in Florida, though, not California. But how does the system benefit everyone? Since it only tells what the truck DID weight, and not what it DOES weigh, isn’t that defeating the whole point of weigh stations? I thought they wanted to monitor truck weights to make sure they weren’t dropping stuff off or picking up stuff illegally or smuggling or whatever.
Maybe I was wrong. So then, why do they weigh the trucks?

The system is called Weigh In Motion. The truck has a transponder that transmits the trucks license plate number and other information. The item on the pole is the receiver for this info. The truck drives over 2 sets of sensors and the weight of the truck is determined. If the truck is close or over it’s licensed limits, the driving receives a signal and stops at the scales just ahead. Saves the truck drivers lots of time if they don’t have to stop. And the reason trucks are weighed is because the trucks are licensed to carry a certain amount of weight. The higher the licensed limit, the more the license costs. It has nothing to do with smuggling or any illegal activities. The reasoning is that heavier trucks cause more damage to the roadways.