40 foot rule on a 48 foot spread axle.

40’ only applies to 53’ trailers.

 

48 spread 10 foot axles. Roll em. No 40 foot here.

Enjoy.

 

You want a reason for Ca bridge laws? This is to ensure that the weight of a vehicle is able to cross the bridge without causing damage. Thats the "official " reason. It also has to do with tight ramps. If your trailer is only 48' then there is no way to extend the length like on most 53' trailers.
A spread axle allows you to use each axle to their capacity because of the spacing. So less concentrated weight then a tandem spaced close together.

 

The bridge law is to protect bridges from damage caused by the concentrated weight of two or more axles closely spaced.

The 40’ kingpin to rear axle law California has does not directly apply to axle spacing. It’s not the bridge law. They are two different, often confused things.

KPRA law is to limit the trailers off tracking in curves and turns.

 

Look up California spreads. Just moves the spreads up a few feet.

 

I should clarify my statement above. 40’ applies to 53’ and longer single trailers. There are some 58’ can vans that run out there.

 

Oftracking and tail swing

I believe it is actually all trailers over 48’

So the 50 and 51’ steps they build fall under it as well. Plus back in the 90’s the Safeway trailers were I think 50’s