My father always talked about a movie he'd seen about gypsy truckers. He's pretty sure that it didn't star George Raft and Humphrey Bogart, so it probably wasn't They Drive by Night (1940).
The boys play brothers who drive a truck, dodging the finance company and drinking coffee in diners to stay awake. Raft is the ambitious one, while Bogart just wants a chance to get to see his wife once or twice. Raft meets up with a tough-talking waitress, Ann Sheridan, setting her up as his girl. But (without giving too much of the plot away), the wife of a friend and benefactor starts to make a play for him. That wife is Ida Lupino and -- OK SPOILER -- she goes totally off the rails for him.
There are a couple of problems with this movie, and one is that it is really two or three different movies - one a realistic but noirish trucker tale, the other a romantic psychodrama, with even a little intermezzo in the middle. Also, Bogart isn't much of a presence here, and is mostly pretty easygoing and mellow (gets a little tense in the middle). And Raft is a pretty stiff actor, although he does have a certain presence.
Sheridan and Lupino are great, though, even if Ida goes a little overboard. And the whole thing has classic feel. Ms. Spenser thought it was pretty silly, I loved it.