by Before there were carjackings, there were auto bandits and thieves. To protect oneself against bandits and thieves, you needed a Colt. Not just any Colt but the Colt Pocket Hammerless Pistol Model 1903 (.32 ACP) or Model 1908 (.380) According to the ad below, it was essential motoring equipment.
I found this wonderful old advertisement on Tumblr where it had been posted by Bubble Head Gun Nut.