There are three categories of transport units. Halftrack units have good road speed. In addition they can travel efficiently overland and can keep up with most main battle tanks through any kind of terrain that the tanks can traverse. Truck units have excellent road speed, but are seriously hampered in their ability to travel off-road. Trucks can enter woods, but unlike tanks and halftracks, they cannot travel from woods to woods.
Trucks can move through rough terrain and gullies, but only very slowly.
While they are sometimes useful for shifting the location of guns in a localized area, they are much too slow to keep up with any other vehicle. Like trucks, wagons can enter woods but cannot move from woods to woods. Scenario designers sometimes include wagons in a scenario's order of battle as an expression of a perverted sense of humor. Passenger Units Transport and Passenger units are natural buddies. Almost by definition, a passenger unit either cannot move on its own or has only a very limited ability to move.