I confess to being a back bumper hitchhiker. This on the N car, from downtown through the Duboce/Sunset tunnel. Back in the 40's. Yes, just a stupid kid. Actually you could only do this during evening commute times. The inside of the streetcar was so full, it was often impossible to get aboard. The conductor was busy, and his view was blocked. So the back bumper made for a way to get home. A cheap ride and an exciting one.