Every shift in Chandler, police officers in cars equipped with special cameras can be seen driving up and down every street in a neighborhood, gathering data on every vehicle in the area.

The cameras, known as automated license plate readers, or ALPRs, scan license plates of nearby cars, capturing images not only of the license plate number, but also recording where the vehicle is located and the time of day, among other things.

As part of the training for the ALPR systems, Chandler officers are taught to "grid" neighborhoods during their downtime – systematically driving up and down every street in an area, indiscriminately scooping up information on vehicles – not because of any suspected criminal activity, but because the information might be useful in future criminal investigations.