What you Should Know
When you’re driving through Arizona, you may not realize just how much your vehicle’s movement can be logged electronically. The federal system known as DEASIL — the DEA’s interface for the National License Plate Reader Program (NLPRP) — is part of a nationwide network of automated license plate readers (ALPRs) that record your plate, location, time, and travel direction.
What is DEASIL and how does it work?
DEASIL gives law enforcement access to a massive database of license plate scans collected by federal, state, and local agencies. Cameras placed along Arizona highways and roads capture your plate using optical character recognition (OCR). That data is stored with timestamps, GPS coordinates, and sometimes even photos of the vehicle or its surroundings.
This information is then searchable by law enforcement for up to 90 days, depending on the agency’s policies. Officers can also place alerts on a particular plate, so they’re notified the moment a scan shows its return to a location.
Why this matters in Arizona
In Arizona, high-traffic routes such as I-10, I-17, and I-8 are common collection points. Because DEASIL aggregates nationwide ALPR data, even a local Scottsdale or Lake Havasu driver can find their movements tracked across state lines or shared between multiple jurisdictions.
This level of surveillance raises important legal questions—particularly when this data is used to initiate traffic stops or justify search warrants.
Privacy and Constitutional Concerns
While one license plate scan on a public road doesn’t typically violate your Fourth Amendment rights, tracking your movement over time could. Courts have held that a pattern of data showing where your car has been might qualify as a “search,” especially if done without a warrant.
Arizona’s constitution offers additional privacy protections under its “Private Affairs” clause, which could give defense attorneys stronger grounds to challenge DEASIL data use in criminal cases.
Also, law enforcement must follow federal privacy protocols. DEASIL users must be authorized and trained. Plate data is typically purged within 90 days if it’s not tied to an open investigation.
How DEASIL Could Affect Your Case
If you’re facing criminal charges or a traffic-related offense, DEASIL data might already be part of the evidence against you. Some potential uses include:
- Traffic stops triggered by alerts from the license plate system.
- Location tracking that places your vehicle near a crime scene.
- Travel pattern analysis, sometimes used to imply guilt or criminal associations.
- Misreads and OCR errors, which can lead to mistaken stops or wrongful accusations.
Defense attorneys must aggressively question the origin, accuracy, and legality of this data.
What You Can Do
If DEASIL data is involved in your case:
- Demand full discovery of all ALPR/DEASIL evidence.
- Challenge the legality of prolonged surveillance without a warrant.
- Verify data accuracy, especially if your plate could’ve been cloned or misread.
- Ask whether DEASIL queries followed agency policies and fell within legal retention limits.
Speak With a Criminal Defense Attorney in Arizona
If you’ve been charged with a crime and suspect license plate tracking was involved, the team at Rideout Law Group is ready to help. We’ve handled thousands of criminal cases throughout Arizona and have experience challenging unconstitutional surveillance tactics in court.
📞 Contact Rideout Law Group
- Scottsdale Office: 11111 N Scottsdale Rd, Suite 225, Scottsdale, AZ 85254
📱 (480) 584-3328 - Lake Havasu City Office: 2800 Sweetwater Ave, Suite A104, Lake Havasu City, AZ 86406
📱 (928) 854-8181
This blog post is for informational purposes only and does not constitute legal advice. Reading this content does not create an attorney-client relationship. For legal guidance specific to your situation, please contact a licensed attorney at Rideout Law Group.