I found this on http://www.opticsplanet.net/police-radar-decatur.html
I don't know how accurate this is except for the fact thay they sell to Police Departments.
State Specific Law Enforcement Police Radar Guns Regulations
Florida: All Police Radars and Law Enforcement Radar Guns must include special "Florida Software". Please contact us when you place your order for a traffic radar or radar trailer to be used a Florida Law Enforcement agency. You must request Florida software at time of order.
North Carolina: No "Faster Target" or "Time Distance (Stopwatch)" modes are allowed in Police Traffic Enforcement Radars. Pre-approval testing required on new models. Genesis I and Genesis II, Genesis VP & GVP-D are currently approved. No Same Direction. You must request North Carolina software at time of order
Connecticut: Hand-held Police radar guns in all forms are outlawed for use by law enforcement agencies. In-car Moving Radars are allowed. Police Radar units must have waterproof antennas and be mounted outside of the patrol vehicle.
Pennsylvania: Stationary Police radars only for use by Law Enforcement agencies. Only State Police are allowed to use police radar for enforcement purposes. On rare occasion, municipal Law Enforcement agencies will purchase a stationary police radar (generally a hand-held device or a speed trailer) to use for conducting speed studies.