Is this real or a computer game   

Dunno, Data. It LOOKS real, but with all of the advancements in game tech, it's possible this was from a game.

It does look real but it is only a game engine, I'm going to give that to you Dave 

The trees give it away I think.

Yes the trees and the lighting for me. Very nice though.

I took another look, and see the point about the trees. When I read you fella's posts, I thought to my self "Trees? What trees?", so I watched it again.

  what game is that? kinda makes me want to start gaming again, starting to miss Trinity, and gaming on her. need to spend some money soon and get her online me thinks 

I don't know what game engine it was done in, I have sent the maker of the video a request to tell us.

After a bit of hunting around and asking people I think the game engine is Forza 5, somehow the Top Gear chaps have got involved with the game.