I made this video using the replay feature recently added to beamng, it's still in early development so it's a bit buggy (You'll notice the vehicles sometimes jitter while moving)
One thing I would like to see from the replay system is the ability to run multiple replays at once. Maybe choose if they overlap or not
I used the built in freecam. You can get into it by using Shift + C then you can use ALT + U to hide the UI for recording. edit: for some shots I did have the camera locked onto the car in freecam (ex. 0:18 in the video)