Shoot the front license plate and get a picture of the person. Oh wait, not all states have front facing plates.

https://en.wikipedia.org/wiki/Vehicle_registration_plates_of...

As a comparision, most of the EU member states have both front and rear facing plates.

Multiple cameras, possibly recording video, could record enough info to fully reconstruc the info on the infraction and get the picture of the driver and the plate even if they're on opposing sides of the car.