License plate readers aren't only for big cities anymore. Exhibit A: Iowa.

The technology is quickly becoming a common way for police to identify wanted criminals or gang members. In Des Moines, Iowa, police began using license plate scanners mounted on patrol cars last year, and Sioux City police will begin using the scanners next month, reported the Des Moines Register.

“We’re just trying to make it right for everyone on the street,” said Polk County Sheriff’s Deputy Jeff Rullman, whose vehicle was equipped with the system at no cost to the county thanks to a $26,000 federal grant. “The number of plates this thing will read on a daily basis compared to what an officer can — it’s no comparison. It’s not uncommon to have this thing run 6,000, 7,000 plates” during an eight-hour shift on a busy Des Moines street.

Used primarily in high-crime areas to identify wanted people, police departments around the country praise the technology for its efficiency. Many systems save scanned plates in a database with the time, date and GPS coordinates of the vehicle for later use by police. For instance, in a child abduction case, the wanted vehicle could be identified much more quickly with a network of stationary and mobile scanners.

This kind of surveillance has also gotten the attention of citizens concerned about their privacy rights. In Des Moines, only one city councilmember, Halley Griess, voted against buying the new license plate scanning systems. “I’m not a conspiracy theorist by any means, but I think it’s a dangerous precedent that our privacy comes at the expense of alleged safety,” Griess said.