Blooper

Brian Donlevy's mustache changes continuously through the film. He goes from bare lip to full mustache to at least two trimmed mustache styles.

The width of the verge (side of the road) where Torrance stops the car to change the tyre is markedly different between the studio shots and the location shot.

When Walter goes to the train depot to inquire when the next train leaves, he has no mustache. Immediately after leaving, he does have one. The presence or absence of Donlevy's mustache varies inconsistently throughout the latter part of the film.

In the Captain's office, when Quincy is asked to investigate Williams' story, a longer shot shows Quincy's hands resting on a desk lamp, while the next closer shot shows them being held in front of him.

When Williams arrives in Idaho, the blood stains on his shirt disappear although the rest of the shirt as well as himself in general is still a dirty mess.

The end credits list the name of the character played by Mae Marsh as "Mrs. Peters"; Marsh played the mother of the gas station owner. The only time the mother's name is mentioned in the film is when Walter Williams first comes to the house for supper, and he calls her "Mrs. King". Marsha Peters (the gas station owner) and her mother would not have had the same last name, since Marsha explains when she first meets Walter that her husband was killed in World War II.

When this movie was made, and in the small town where this character lived, a woman would not have kept her maiden name when marrying or returned to it after being widowed. She would have remained Mrs. Peters unless she remarried.

When Williams, Marsha, and her mother get set to eat dinner, Williams is dressed up in a suit, tie, and clean shirt. How did he get that way? After the accident he had nothing but the clothes he was wearing which showed the signs of the accident. However, when Williams leaves the garage to go to the barber shop, Marsha says to "Tell Judd, you're working for me." It's likely that Judd set up Williams with the wardrobe, either some of his clothes or from a haberdasher who would grant credit based on Williams working for Marsha.

After Jim takes over driving from Walter, on the rear-screen projection behind them, Jim is constantly driving on the wrong side of the road. This may be from a front-facing shot run backward or a rear-facing shot reversed.

When Walter first meets Marsha working in the garage, she is wearing work shoes with coveralls. However, the foley sound of her walking is that of a woman in heels.

When Irene sends a telegram, the clerk says $1.35, Irene mouths the words "thank you" however you don't hear anything. Additionally, the audio of the clerk is dry and void of ambiance making it very obvious that line was overdubbed.

The Bekins truck drivers should have been able to testify that the driver of Williams' car was Torrence and not Williams. Even if they didn't see him clearly, they could certainly testify that the man who drove off was subsequently killed is the collision with the tanker truck. Since Williams was alive, it could only have been Torrence who sped off and therefore could not have been killed by Williams.

When Marsha tries to convince Walter/Bill that he has to return to San Francisco and tell his side of the story, the shadow of the boom is visible on the wall behind them.