bozer, that has been discussed many times here. I think the real answer was in a GM advetisement that Denny Graham(?) posted here some time ago for an early GM car that in the add mentioned this.
My memory may not be the best or I could be wrong about the video but I do know it had to do with safety. Folks would lock the driver side and then slide out on the "street" or "boardwalk" side to keep from getting hit......
