Eman,
Firstly I hope you're OK! Did you get whiplash?
Secondly, did you get his reg no? I would respectfully ask that you take this a step further. Could you contact the police again and speak to someone else about what happened and about how sure you were that he was drunk. I know that the police will sometimes monitor someone if they're strongly suspected of drink driving, they might even pull him up on his way home or something next time. I know of one person who was suspected and they pulled him up around the corner from his local pub and banned him for 3 years.
Sirona