Sen. Todd Weiler, R-Woods Cross, is writing a bill to launch the debate and is proposing as a starting point to allow keeping data for six months and ban all public access to it, such as subpoenas from divorce lawyers trying to prove that someone is having an affair.
Weiler explains how he saw one such machine work during a police ride-along.
"If I am in this vehicle traveling 80 miles an hour in one direction, and you pass me on I-15 traveling 80 in the other direction, we can read your license plate and know immediately if your car is stolen, if the insurance is expired or if you haven't paid your fees to the state," he says.
"Or let's say you are parked at Walmart. This car can just meander through the parking lot and in a matter of minutes read every license plate and know if any of them are stolen or have other problems." He adds police in Utah are recovering about 1,300 stolen vehicles a year with that technology.
"It's kind of cool on one hand," Weiler says, "and on the other hand it's kind of creepy."
Last summer, worry about the "creepy" side torpedoed a request by the U.S. Drug Enforcement Administration (DEA) to put readers on freeways in southwestern Utah to record the license plate numbers of all vehicles there to help catch drug runners, as it does in drug corridors in Texas and California.
Weiler co-chairman of the Law Enforcement and Criminal Justice Interim Committee says the request created a firestorm among some lawmakers and members of the public worried that government could track their movement and potentially expose trips they want to keep private, such as heading to casinos over the state line.
While the DEA withdrew its request amid the controversy, Weiler says lawmakers learned that numerous police agencies already are using mobile license-plate readers. "So the discussion opened a can of worms that we are trying to deal with."
A Salt Lake Tribune review earlier this year identified 47 police agencies statewide that use license-plate scanners or have permission to borrow some owned by the Utah State Tax Commission, and no state law governs their use.
Marina Lowe, an attorney for the ACLU, says the civil rights organization would like to limit storage of the data to about 12 hours. "That would allow finding such things as stolen cars" during one police shift, which she sees as legitimate.
She worries that longer storage could lead to tracking or profiling people without legitimate cause including recording license plates of cars at protests or recording them at bars to target people for being pulled over for drunken driving.
On the other extreme, Beaver County Sheriff Cameron Noel who testified in support of the DEA request for scanners on Utah freeways says, "I think that data should be available indefinitely."
For example, he says, his office recently took months to develop a suspect in an armed robbery. "It would have been a really nice piece of information to find out if he drove through our county that particular night. That would be good evidence to have for a court."
He says storing such information for years could help solve big crimes such as murder and kidnapping, and not just minor offenses such as stolen vehicles which is what they are used for now. Increased use could help more quickly find where kidnapping or robbery suspects are driving and where they may be headed, he adds.
Lowe, Noel and Weiler all agree on one thing: This information should be available only to law enforcement agencies investigating crimes. Weiler says he wants to clarify that such data could not be subpoenaed in civil cases.
Noel says such a restriction could help ease public queasiness about using the scanners. "There is a concern. [People] believe they are going to get caught going to Las Vegas or get caught going to see their girlfriend in St. George, or whatever it may be. They don't want somebody to be able to get those records. I understand that."
Weiler says he expects a lively debate. "That is no clear right or wrong answer," he says. "But I want the debate, and to put this into state law and not just in administrative rules."