It was largely disallowed. Men made all the money, automobiles were expensive and complicated, and it was still considered uncertain if women were capable of handling the complexity.
Our history is full of examples of activities effectively prevented en masse by society without being explicitly illegal.
Just because our past is embarrassing doesn't make it untrue.
Edit:
With regards to how it integrates into my comments about drunk driving and designated drivers; having women become generally accepted as peers in the operation of automobiles changed the parameters for purchasing the vehicle for the household.
If I'm going to continue drinking regularly, and I'm no longer allowed to drive drunk, and we collectively regard women as perfectly acceptable behind the wheel - I'm buying a car that I know my wife can drive as well as I can, not necessarily my preferred model.
It was largely disallowed. Men made all the money, automobiles were expensive and complicated, and it was still considered uncertain if women were capable of handling the complexity.
Our history is full of examples of activities effectively prevented en masse by society without being explicitly illegal.
Just because our past is embarrassing doesn't make it untrue.
Edit:
With regards to how it integrates into my comments about drunk driving and designated drivers; having women become generally accepted as peers in the operation of automobiles changed the parameters for purchasing the vehicle for the household.
If I'm going to continue drinking regularly, and I'm no longer allowed to drive drunk, and we collectively regard women as perfectly acceptable behind the wheel - I'm buying a car that I know my wife can drive as well as I can, not necessarily my preferred model.