I have very limited knowledge on the subject. I have been told that a many parking spots were a parallel spot. The streets were not always as wide as they are now. For safety reasons, auto manufactures only installed a outside lock on the passenger side. This was to encougage the driver to exit that side of the vehicle, in order not to open their door into traffic. I don't know that is the reason. But, that is what I was told when I asked someone that drove the 50's trucks, new in the 50's. If somebody else has another explanation, I would be interested in learning more about the reason or reasons also.
Rugo
