Traffic radar used by police uses frequencies in the X-band (10.5 Ghz); K-band (24.125 Ghz); In the early 90s there were reports of police officers contracting testicular cancer from using handheld radar guns.  Officers in Windsor Locks, CT had used hand-held radar guns for years, sometimes resting them between their legs while waiting for speeding cars to approach. Three of them sued the manufacturer for causing testicular cancer.
Connecticut State Police and a dozen municipal departments stopped using handhelds in October, '91. The State's two largest police unions advocated using only the units with transmitters mounted outside the vehicle, away from the officers.  Connecticut then banned handhelds altogether,  opting instead for laser-based speed trapping
"Professional law enforcement publications first raised the issue about potential health risks from the microwave radiation emitted by radar guns in 1990." A Newport News, VA officer similarly rested a radar gun in his lap and also contracted testicular cancer. His and other Virginia police departments took precautions similar to their Connecticut peers. "An Ohio Highway Patrol trooper charged that microwave emissions are causing injury and death to police officers who use the hand-held radar guns." In St. Petersburg, Fla., the police chief had the guns tested. He found two different theories on their safety:
Academics said research was incomplete but to use caution. The government and military said there was no problem, which left him with a dilemma, so the bought new two-piece units with the radar emitting antenna on the roof. 
The National Institute for Occupational Safety and Health has found no concrete evidence that radar guns cause cancer yet recommend they not be used very close to the body; that handhelds be equipped with a "dead-man switch" that must be held down for the device to emit radiation; that radiating antenna of older handhelds without a "dead-man switch' should not be pointed toward the body; otherwise that two-piece units be used with the transmitter mounted outside when possible. 
Similar to OSHA, the World Health Organization does not find evidence for risk of cancer from radars under normal circumstances. Epidemiological studies and peer review groups have found no clear evidence of links between RF exposure and excess risk of cancer - except that RF is a Class 2B, Possible Human Carcinogen.  WHO also concludes there is no convincing scientific evidence that exposure to RF shortens the life span of humans, or that RF is an inducer or promoter of cancer. However, they concede that further studies are necessary. 
Occupational exposure of this kind seems to have been addressed appropriately.