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Radar Detector Legality: What US Drivers Need to Check

There is no single rule for every driver and vehicle. Check state law and federal commercial-vehicle restrictions before using a detector.

Radar detector legality in the United States depends on the state and vehicle. Federal rules prohibit detectors in certain commercial motor vehicles, and signal jamming is a separate issue from passive reception. Check current statutes and regulations for every jurisdiction and vehicle you use.

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Rules and how they work

Legality by state

Common questions

Questions before you buy

Are radar detectors legal in the United States?

Rules depend on state, vehicle type and location. Federal law restricts radar detector use in certain commercial motor vehicles; check current federal and state requirements.

Are radar jammers legal?

Jamming or interfering with law-enforcement speed-measuring equipment is prohibited under federal law, and states may also prohibit it. A detector receives signals; a jammer transmits interference.

Can commercial trucks use radar detectors?

Federal regulation 49 CFR section 392.71 prohibits use of radar detectors in certain commercial motor vehicles. Review the current regulation and its definitions for the vehicle involved.

Can I use a detector in a military installation or other restricted area?

Site rules may restrict devices even where ordinary road use is permitted. Follow posted instructions and applicable local authority requirements.