a big rig
NO
Depends on the weight class and/or organization you are pulling with. Generally speaking weight classes are 6200,6350,5800,and 6800 lbs.
Dually, slang for having two wheels and each side on a single rear axle.
The mail van used by the USPS nowadays is the http://wiki.answers.com/wiki/Grumman_LLV. This is a custom-made mail van manufactured by Grumman Corporation, whose USD 1.1 Billion dollar contract with...