Jonathan,

the equation on page 352 of the 2nd edition does not include the effects of the tractor trying to keep the trailer from rolling over. In the 4th edition the equation was changed to include the tractor. Hence, example 22.6 was dropped. The 5th edition was published in 1999. A complete explanation of the constant 0.1 may be too difficult to accompish via the discussion forum. In short, it takes care of the change of the center-of-gravity location reducing the rollover moment, and also reducing the stabilizing moment. Please, e-mail me your address so that I can mail the derivation and the complete equation.

PCB 11-2006 will discuss, among other subjects, tractor/trailer rollover with MARC1 application.
Please, down load it. It should be up on our website
by September 11, 2006. If you want to call, please do so on my cell phone 801-201-2532.

Thanks, Rudy Limpert