The cameras will run the license plate of every car passing through against a hotlist database.
If the car is stolen, or if the vehicle is the subject of an Amber Alert police will be notified.
Paradise Valley Police say it's to cut down crime, others claim it's an invasion of privacy.
FOX 10 saw the cameras being installed and initially Paradise Valley Police were going to do an on-camera interview about the license plate readers, but hours before our interview they cancelled saying they did not want to do any interviews until all the license plate readers were in place and operational. Crews installed the first camera on Wednesday.
Crews installed that reader atop a Paradise Valley traffic light at McDonald and Tatum. It's the first of 11 cameras that will scan license plates of everyone driving to and through the city.
"I totally think it's a great idea... it just keeps everyone in check, and if you don't have anything to worry about, then you don't have anything to worry about," said Kathy Merceri.
Paradise Valley Police say the readers pull information from a Department of Public Safty hotlist that includes cars that are stolen, associated with fugitives, or are the subject of amber or silver alerts.
If a license plate matches, the dispatch center is notified, and the closest patrol car can respond.
"I mean I think it's good for stolen cars and all that, I just think technology is getting crazy now a days, it's kind of scary what people can do now," said one hiker.
"You're not just pulling information on stolen cars, you're pulling information on everyone's car and that is kind of intimidating," said another woman.
Police say the system does retain information, but they could not say for how long.
"Which is pretty telling in of itself, these things in our opinion should not be put in place at all... but they should never be put into place without clear guidelines and retention policies, whether it's this type of thing, body cameras or whatever without that, it demonstrates a disregard for people's privacy and rights," said attorney Dan Pochoda.
One woman now has a renewed hope that she may be reunited with her stolen car. "Maybe it will catch and return my car one of these days, it's been two years now," said Merceri.
On top of the fixed license plate readers, all Paradise Valley Police cars will have the readers on them. The first camera FOX 10 saw being installed Wednesday will likely be operational on Thursday, but they are still testing them and working on a policy.