Do motor bike lap timers work on cars?

[shortshift]

The lap timers listed on eBay for bikes are a fraction of the price of the lap timers for cars but must do the same job. They don't connect to any of the electrics or mechanics of the vehicle so are simply receiving an infra red signal. I wouldn't have thought is would matter if the vehicle was a car, a bike or a skate board?

EG: http://www.ebay.co.uk/itm/390950108952?_trksid=p20...