Santiago de Chile
Go to "San Bernardo" - either by Microbus or by hitchhiking. I hitch hiked there but had to wait 1 hour to get to San Bernardo.
There you will find a Bus station next to the Ruta 5. Don't go there. Also don't go to the Ramp. The cars are just locals wo dont go far.
BUT: Go to the main Road of the Ruta 5. There will be a good spot to wait. The cars go damn fast, but there is space to pull over the car. I waited lmost 1 hour to get out. Switching from the ramp to the side and the main road until finally a truck stopped for me.