There are license plate readers all over the Bay Area that law enforcement can use to track vehicles coming in and out of a particular area. Many of these devices have hung above street lights for a few years, but now some East Bay cities are beginning to limit what surveillance data is being collected from them and regulate how that data can be used. Guest: Cyrus Farivar: Ars Technica, senior technology policy reporter and author of Habeas Data: Privacy vs. the Rise of Surveillance Tech