It Still Runs is the go-to destination for all things cars. From motors to radiators and everything in between, we've got you covered.


Bobtail Truck Definition

by Will Charpentier

Two kinds of trucks carry the moniker "bobtail." Both are short, like the tail on a bobcat. One is a semi tractor without a trailer. The other is a straight truck, in which all of the truck's axles are attached to the same chassis. Straight trucks that transport propane gas are also known as bobtails.


In trucker's slang, a bobtail is the tractor part of a semi. Usually truckers "run bobtail" when they have no trailer to pull. For example, when they leave a loaded trailer at its destination and must drive to a new location to pick up a different trailer, the tractor alone, because it's shorter than a tractor and trailer, is called a bobtail.

Short and Straight

The U.S. Department of Energy calls a straight truck that's used to carry propane a bobtail. Such trucks, DoE says are powered by propane and have a tank that's significantly shorter than other petroleum transport trucks.

About the Author

Will Charpentier is a writer who specializes in boating and maritime subjects. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. He is also a certified marine technician and the author of a popular text on writing local history.

More Articles

Photo Credits

  • Tim Boyle/Getty Images News/Getty Images