This article is from the The Monster Truck FAQ, by Jeff Hawkins with numerous contributions by others.
A. For the purposes of this FAQ we'll call a Monster Truck a highly modified
four wheel drive vehicle. The most distinguishing characteristic is the
extreme oversize tires.
Most monster trucks are speed and handling enhanced in order to race
similar trucks over obstacle courses usually set up with cars to run over
(crush), dirt ramps to jump, possibly a little water puddle, and a drag
racing style timing system.