In classic detective novels, a plucky private investigator sometimes spots the license number of a suspicious car and wheedles his pals at the DMV to "run the plate" and match it with a name and address. But modern technology has exponentially increased the amount of license plate information available to law enforcement and to a thriving private industry of license plate scanners. A bill that would have set privacy standards for the collection and storage of license plate data has stalled in the state Senate, but the issue isn't going away.

License plates are now automatically photographed by cameras mounted on both vehicles and stationary objects such as poles, and the license numbers are entered into databases along with locations, dates and times. This can help police determine where a particular car was at a particular time, or figure out what cars were in the area when a crime was committed. The L.A. County Sheriff's Department reported having 84 vehicles outfitted with plate readers, and 47 more in fixed locations. An LAPD official said it had 240 car-mounted units and 30 fixed ones. In addition, police agencies often obtain license plate information from private companies such as Vigilant Solutions of Livermore, Calif., which has more than 3,500 law enforcement clients.

It's easy to say that no one has a reasonable expectation of privacy when driving on the streets or parking in a public place. But changing technology — especially the digitizing of license plate photographs and an almost endless storage capacity — has dramatically widened the window through which police can track an individual's comings and goings.

Like GPS technology, which allows police to track the movements of suspects through their cars and telephones, the proliferation of license plate scanners demonstrates the need to adapt traditional notions of privacy to new and invasive technologies. The American Civil Liberties Union has proposed several recommendations to protect privacy: Police must have reasonable suspicion that a crime has occurred before examining collected license plate data; citizens should be able to find out if data about their license plate are contained in a database; license plate data should be deleted after a short period to avoid fishing expeditions; and law enforcement shouldn't share such data with third parties that don't adhere to these protections.p>

State Sen. Jerry Hill (D-San Mateo) introduced a bill that would have required private companies to safeguard license plate data in their possession and would have placed reasonable restrictions on the use of such data by law enforcement. Unfortunately, the proposal failed to win approval. We hope Hill redoubles his efforts to enact a meaningful bill when the Senate returns.

©2014 the Los Angeles Times