Several items of clothing worn by Steve McQueen received a boost in popularity thanks to the film: desert boots, a trench coat, a blue turtleneck sweater and, most famously, a brown tweed jacket with elbow patches.
Although Steve McQueen was credited with the driving during the chase sequence, it was actually shared by McQueen and Bud Ekins, one of Hollywood's best stunt drivers. From the interior shots looking forward inside the Mustang, it's easy to see which one is driving. When McQueen is driving, the rear view mirror is down reflecting his face. When Ekins is driving it is up, so his face is hidden.
While filming the scene where the giant airliner taxis just above Steve McQueen, observers were shocked that no double was used. Asked if the producers couldn't have found a dummy, McQueen wryly replied, "They did."
Bullitt's reverse burnout during the chase scene actually wasn't in the script; Steve McQueen had mistakenly missed the turn. The footage was still kept, though.
The device used to transmit the photos of the Renick couple over the telephone line was one of the original facsimile machines, and in fact the device from which the generic word "fax" was derived. It is the Xerox Magnafax Telecopier, introduced by Xerox in 1966 and considered a revolutionary technical breakthrough. Until this device appeared, facsimile machines were large, heavy, and difficult to operate.