In relation to trucking, a tractor is the power unit used to pull or draw a trailer. The same concept applies to the tractor used in the field. It is often used to pull or draw implements designed to perform certain tasks. A tractor used to pull a trailer on the highway is often called a road tractor. It has most of the features found on any
motor vehicle used on the highway, and some others which are specific to the trucking industry. Road tractors can be equipped with the most sophisticated audio equipment, A/C,
satellite dish TV reception and many other creature comforts. An example of specialized equipment is the sleeper cab, a means whereby a driver can take his required rest breaks without the outlay for a
motel room. Another is a QualComm unit, a satellite based communications system that allows real time communication without reliance on
telephone service. This system can be custom designed to include
GPS, give vehicle operational information, let dispatch know where the unit is at any given time.
Road tractors come in a variety of configurations specific to the task which they are required to perform. There are sleeper and non-sleeper units. There are units with 1 or more drive axles, while others have 'tag' axles, which are non-powered axles which still allow a higher weight to be pulled. The variety is almost endless but all have the same purpose, that being to pull some type of trailer.