How much does a semi-truck weigh?

Answer 1

16,000 - 20,000 lbs usually for the front part ("truck", "tractor", "cab"). But the empty trailer adds several tons more. For example a 53 foot long simple box ("van") trailer weighs 10,000-15,000 with nothing in it. So a whole 65 foot long empty system (truck and trailer) weighs over 30,000 lbs. Shorter box, flatbed, and covered wagons systems would weigh less. Systems with an extra long truck or specialized systems, like some of those with tank and pumping equipment, may weigh more.

ADDED: Also, state regulations can, and do, vary as far as the length of the rig and the maximum allowable weight. That is one reason you usually see "weigh stations" very close to the state lines on most interstates and other heavily trafficked highways.