It's publicity rather than anything else. Gets a message out from the Police (as it seems to be doing here) that they're concentrating on speeding and will touch a nerve with a few people. Also, it's publicity for Atom who are releasing their new bike sometime soon. The car will be dragged out for open days, displays, etc. and will turn up at biker meets where they'll have a chat with bikers about speed, rather than being used in earnest to catch speeding bikers.