The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with hitch a ride
thumb a ride. Solicit a free ride, especially by hitchhiking. For example, I've no car; can I hitch a ride home with you? or He was hoping to thumb a ride to the stadium. The verb hitch here alludes to walking unevenly, presumably to hop into a car or truck; raising one's thumb is the traditional signal for stopping a car on the road.
[ First half of 1900s