What is the rationale for the Bridge Laws?

I cannot answer your question because I cannot tell from looking at the picture which tractor-trailer has a longer distance between the kingpin and the rear axle.

 

Yes, the trailer is the bridge between two points. Your drives and the trailer tandems.

 

Well, logically, that is what I would have expected to. A longer wheelbase would put less strain on a bridge than a shorter wheelbase, for a given weight. But the bridge laws I've seen in company handouts at all the trucking companies I worked for say otherwise.

What is KPRA? I've never heard or seen KPRA before I created this thread.

 

Assume they're the same.

 

Bridge laws are designed to assign responsibility to the driver when swift runs into them.

 

The distance between two axles in tandem or spread is also a bridge.

 

I'm not saying that you're wrong. But I have never heard of that before in 8 years as a truck driver.

 

I cannot tell which one would be allowed to gross more weight from the pictures. Both tractor-trailers have eight axles, and the wheelbase is the same on each.

 

There you go, man. You literally understand bridge law.

Now that you know bridge law involves weight tearing things up, KPRA covers length tearing things up. If the KPRA is too long, you'll be hitting signs with the middle of your trailer. Shorter KPRA makes the trailer more nimble, at the expense of increasing tailswing.

 

Your trailer has a tandem. Mine has a spread. You can put 34k on your tandem, but I can put 40k on my spread because the weight is spaced out farther.

So in his pic, assuming KPRA is the same, look at his axle groups.