hi there bright minds...
my team and i are into this project called the safety steering wheel, we are trying to apply proximity sensors which will detect the distance of other vehicles or objects on the road. we are looking for long range sensors which will depend on the speed of your vehicle,the higher the speed,the longer the range gets, maybe you guys can hit me back if you have any ideas,thanks in advance...peace out!=)

 

As far as I am aware, the industry (BMW, possibly Mercedes) uses radar for the distance sensing. No idea about frequencies or output power. At a guess, it's going to be low enough to avoid attenuation by rain. Don't think this come off the shelf.