Police officers are sworn employees of the jurisdiction for which they work. They are charged with the duty to protect life, property and public safety while apprehending those who violate the law.
It is a well-known and proven fact that visible patrol in a plainly marked police car is the best deterrent to speeders and other wrongdoers. Such patrols allow the officer to stop the violator then and there and put an end to the unsafe act. Stopping the violator also enables the officer to determine if the suspect is impaired or operating an unsafe vehicle.
Placing the officer in a motor home to take pictures and record the speed of a violator does nothing to protect others. The speeding suspect continues down the interstate endangering life and property. Should an accident follow, I could almost envision a case of dereliction of duty against the officer and/or his municipality. Certainly a learned attorney could fashion a lawsuit on the premise that the officer failed to perform his duty, and by not stopping the violator shares in the liability thereto.
As a retired member of the Los Angeles Police Department, I say the traffic cameras are nothing but a "speed trap" whose purpose is to collect revenue, and they do nothing to protect life and property.
If allowed to continue, they should be manned by "tax collectors" not "police officers."