Louis L'Amour's memoir, "Education of a Wandering Man", said this movie was actually based on his own war-time anecdotes.
He was awarded two Bronze Star Medals while serving as an officer with the Red Ball Express.
James Edwards was originally cast in the role of Robertson, but was fired during production when he refused to testify before HUAC. He was replaced by Sidney Poitier.
The vast majority of trucks used for this picture - and for the real Red Ball Express - are GMC CCKW-353 2 1/2 ton 6x6. About 572,500 of all variants of the CCKW were made from 1941 to 1945.
When the American tank crews are watching the French town burn, one of them comments that the fires are "burning like election night." He was referring to an old common practice in east coast US cities, where bonfires often blazed on election night as a form of celebration. Huge crowds used to gather in the streets to hear election results before the invention of radio and television. The tradition has since died out and no longer occurs.
The tow truck seen in this film is a 1941 Diamond T 969A "wrecker" model. Over 30,000 Diamond T 4-ton 6x6 trucks of all variants were made from 1940 to 1945.