Thought I would experiment. I rigged the tripod on the back seat of the car (safely!). Put the camera on top and used the auto-focus to focus on the internal mirror – I did this bit during the day. I then switched the auto focus to manual in order to stop it from searching. I used the largest f number in order to get everything in focus. I also used a remote control trigger – which my wife used – gotta be safe. I waited until I came to an area where there was enough light over the motorway and voila!