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20,000 - Facts of the Federal Bridge Law

Yahoo Message Number: 10382
The following web site documents the details of the Federal Bridge Law and the 20,000 pound per axle limitation...
http://www.randmcnally.com/pdf/tdm/Federal_Bridge.pdf
An easier-to-read version of the law (including telephone numbers of each state to call for questions) can be found at:
http://www.hendrickson-intl.com/literature/bridgelaws/
An excerpt follows:

"Gross Weight?The weight of a vehicle or vehicle combination and any load thereon. The Federal gross weight limit on the Interstate System is 80,000 lbs. Single-Axle Weight?The total weight on one or more axles whose centers are not more than 40" apart. The Federal single-axle weight limit on the Interstate System is 20,000 lbs.
Tandem-Axle Weight?The total weight on two or more consecutive axles more than 40" but not more than 96 inches apart. The Federal tandem- axle weight limit on the Interstate System is 34,000 lbs.

Interstate System weight limits in some States may be higher than these figures due to "grandfather" rights. When the Interstate System axle and gross weight limits were adopted in 1956, States were allowed to keep or "grandfather" those which were higher. In 1975, States were also allowed to keep "grandfathered" bridge formula limits which were higher than those established for the Interstate System."

Note: There is no exception for RVs noted in the law.

Re: 20,000 - Facts of the Federal Bridge Law

Reply #1 –
Yahoo Message Number: 10385
If you read this and look at the site explaining the need for the weight limits it looks to me that RV's fall into the 34000# category.
The Single Axle Weight states the axles are "not more than 40 inches apart". Mine certainly are greater than 40 inches apart so this does not qualify.

The Tandem refers to consecutive axles "more than 40 inches but less than 96 inches". This more closely describes my (what we call non-tandem) axle setup. When I look at the drawing on the site it would appear that the problem the formula is trying to solve does indeed more closely relate to my configuration.

So it appears to me 34,000 is the legal limit for the rear.

Dave

Re: 20,000 - Facts of the Federal Bridge Law

Reply #2 –
Yahoo Message Number: 10391
Dave; If your coach has a tag axle, your legal limit on the combined rear axles (drive and tag) would be 34,000 lbs; if no tag, then your legal limit is 20,000 lbs on your drive axle. The drive and tag axles are generally about 48" apart and are consider "tandem axles" according to the Federal Bridge Law.

Bob

Quote from: tandemsince83
> If you read this and look at the site explaining the need for the > weight limits it looks to me that RV's fall into the 34000#

category.

Quote
>

The Single Axle Weight states the axles are "not more than 40

inches

Quote
apart". Mine certainly are greater than 40 inches apart so this

does

Quote
not qualify.

The Tandem refers to consecutive axles "more than 40 inches but

less

Quote
than 96 inches". This more closely describes my (what we call > non-tandem) axle setup. When I look at the drawing on the site it > would appear that the problem the formula is trying to solve does > indeed more closely relate to my configuration.

So it appears to me 34,000 is the legal limit for the rear.

Dave

> An excerpt follows:
>

> "Single-Axle Weight?The total weight on one or > > more axles whose centers are not more than 40" apart. The

Federal

Quote
single-axle weight limit on the Interstate System is 20,000 lbs.
>

> Tandem-Axle Weight?The total weight on two or more consecutive

axles

Quote
more than 40" but not more than 96 inches apart. The Federal

tandem-

Re: 20,000 - Facts of the Federal Bridge Law

Reply #3 –
Yahoo Message Number: 10395
Bob -

I don't have a tag and my axle's only rated at 19,000 anyway so I better not exceed 20K :^), but when I read the regulation it pretty clearly says the other axle had to be within 48". I guess I was reading it out of context and it was only about tags.

Dave

'98 Allure #30187

Quote from: rvrobert2003