Why does Milton Arbogast exit his car by sliding across to the passenger side an...

In Psycho (the original), Milton Arbogast exits his car by sliding across to the passenger side and getting out through the right hand door. Why? I am guessing that either the car was not a complete unit, or that the film crew was too close to the car for him to exit the normal way.

This actually happens everytime somebody exits the car in the film (and in quite a few other films from the era too).

There are two possible reasons for this:

Firstly, Hitchcock did love his filming and it's highly possible he felt having the people exit via the passenger door gave him a better shot. In fact, some basic googling shows a general consensus that Hitchcock preferred to continue a shot without moving the camera to either follow the actor or to have the actor walk between the camera and the car (although I can't find an interview with Hitchcock to corroborate this).

However, secondly and probably more importantly, this action used to be what was recommended in the 1960s. I remember discussing it with a friend of my father's. His car, like the car in the film, had bench seats like this:

It was considered safer when parking to shuffle over to the passenger door so you were stepping out onto the pavement, as opposed to using the driver door and exiting into traffic. Nowadays, where the bench seat is gone and two distinct seats are in place, it's not as comfortable or convenient to do this.