How can a WIM scale detect an overweight axle on a personal vehicle that isn't communicating data to it?

 

​​​​​​Commercial Trucks don't all have transponders. Some WIM have electronic signs that say "Truck okay to bypass" or "Truck must enter scale"
Some don't even have a truck parking area just a small building or a interface to hook a van to and they use chase cars and portables to confirm weights.

Some scales require all trucks over 8,000 lb to enter not just commercial.

 

Usually when I see the signs "8,000 to enter not just commercial ", most RV'ers just fly by. Just occasionally over the past 20 years I see a few in line or being pulled over.

 

There is a person or two watching cameras, and if not mistaken, the weights registered by the plates at that location display on the screen. It is possible the person monitoring knows what the axle weight is for that particular truck that got pulled in and knew it was over weight, maybe they own one themselves. Of course this is just speculation, I really have no idea why that particular rig was called into the scale. I didn't catch the state it was from either, but it could also be that the plates were of the wrong class for the weight.

Only thing I can tell you is, make sure you properly register the truck, and try not to exceed the GAWR.

 

Gene made a good point, failing to obtain an interrogation response so the registration can be pulled, the system just automatically issues a pull in warning.

Came across a comment that they now have systems that read license plates to pull registration and signs so a pre-pass system isn't required. That would make it easier for those of us driving private vehicles and not knowing when a state doesn't or doesn't want to weigh half-ton combos, non-commercial 3/4 tons, etc.

 

I'm trying to remember who it is that just says "All Trucks over 8,000 must Weigh". I'm thinking it's Nebraska but could be wrong.

Regardless, like a lot of things it doesn't really matter what the law is but how they choose to enforce it. I almost never see a private vehicle pulling a travel trailer enter a scale (even when signage would indicate they should) and I never see them pursued so suspect enforcement policy is to simply ignore it.

 

In some places, yes, and probably time of day. If there are a lot of commercial drivers on the road, I'd think they would concentrate on them.