Firstly its a 24FPs game is at 60FPS, also speed is all relative as explained earlier many games speed things up, NFS, Burnout etc to give you an artificial look of speed that is unrealistic.
But it looks unrealisticly slow for the speed... When you see internal views on real cars going around tracks it looks a hell of a lot faster.
When I took my old scooby to Donnington doing 150 looked considerably faster the videos all look a bit driving miss daisy but as i said it may just be the videos making it look like that..