Rear Window - Thriller Opening - Harry's post

The first shot is an extreme long shot behind a wooden fence on a bend in the road with a car at night driving towards it.  It is a very simple shot with only diagetic sound in it. This shot is purely to set the scene.

This shot is followed by a cut to a women in a car on the phone...

This is a medium shot of her on the phone whilst driving, there is still only non diagetic sound and the lighting is quite low key focusing mainly on her upper half.

She is on the phone whilst driving which creates an instant threat which everyone notices

The characters costume looks like she is a business women, which is backed up by the conversation she is having on the phone (explaining that she is going to be late) maybe from work? 

As the women loses signal she tries to ring the person back, whilst doing so she edges onto the other side of the road and surprise surprise there's an on coming car. 

Using an extreme long shot allows the viewer to gain dramatic irony of whats about to happen as the women is not concentrating. Having this scene at night allows the lights of the oncoming car to add a much more dramatic effect to the whole shot.