License plate reader (ALPR) searches should require a warrant for historical data, argues a tech expert who works with police. In Schmidt v City of Norfolk, the court ruled against plaintiffs but noted mass surveillance could become too intrusive, saying "not today." The author believes cameras will be ubiquitous, so the question is when, not if, warrants will be needed.

Current case law from Carpenter vs US requires warrants for cell-site location data due to its comprehensive tracking. Recent decisions like Chatrie (geofence warrants) and Beautiful Struggle v Baltimore (aerial imagery) support that ALPR data will eventually need a warrant. ALPR cameras cost under $3,000 per camera and are cheap enough to have positive ROI even with modest crime reduction.

Historical searches (e.g., tracking a plate over 30 days) differ from active flags (immediate stolen vehicle alerts). Exigent circumstances may justify short-term searches, but New Hampshire's 3-minute retention is too short. The author argues states should mandate warrant procedures to protect privacy without hindering legitimate investigations.