Detection of hidden cellular GPS vehicle trackers

Automated License Plate Readers (ALPR) and Corporate Surveillance

• Discussion quickly broadens from the paper to ALPR networks (e.g. Flock-style systems) blanketing US roads, malls, and big-box retail parking lots.
• Several note that “30‑day retention” claims often apply only to images; OCR’d plate + timestamp metadata may be kept indefinitely or shared across agencies and private collaborators.
• Commenters mention wide coverage on interstates and urban corridors, facial recognition on front-seat occupants, and easy vehicle recovery by repo/tow companies using commercial LPR networks.
• Concerns include law-enforcement fishing expeditions (including abortion-related searches) and long-term retention of location/phone records.

Other Tracking Vectors Around Vehicles

• Bluetooth and BLE: debate about range (20 ft vs hundreds of feet with directional antennas/custom hardware). MAC randomization now common on phones, but unclear and inconsistent on cars.
• Wi‑Fi MAC tracking in stores was common; newer devices randomize per-AP but not universally.
• TPMS and tire RFIDs: wireless tire sensors can broadcast trackable signals; contrast with ABS-based pressure estimation which is not radio-based.
• APRS and truck/semicam dashcams show that “old” vehicles can be tracked too.

Stalking, Theft, and “Security Nihilism”

• Some argue location privacy is already lost to data brokers and mobile apps, so hardware tracker detection is marginal.
• Others push back: stalking and car theft are narrower threats where detecting a physical tracker still meaningfully helps victims.
• Disagreement over whether the real battle should target app ecosystems and data brokers vs specific covert devices.

Technical Behavior of Trackers and Detection Challenges

• Many trackers use motion sensors or voltage sensing to enter low-power mode when parked, transmitting mainly in motion; this complicates pre-theft scanning.
• Some devices store data locally for manual retrieval to avoid RF detection.
• GPS-based movement detection is power-hungry; accelerometer/IMU triggers are far cheaper energy-wise.
• Discussion of detection tools: RTL‑SDR vs tinySA; narrow bandwidth and IoT sharing bands with normal LTE make layperson detection nontrivial.
• GPS spoofing/repeating is floated as a detection/defeat method, but others warn it is legally and technically risky.

Legal, Policy, and Dealer-installed Trackers

• EU commenters note that private ANPR on public roads is generally unlawful under GDPR, though parking lots use ANPR for access control.
• Debate over how effective GDPR really is vs how easily companies lean on “legitimate interest” and consent.
• Reports that some dealers or dealer groups covertly install OBD-based trackers on new cars for insurance or upsell, detectable via unexplained battery draw in EV telemetry.