Radar Detectors in New Jersey: Legal in a Private Car, Banned in a Truck

The Legislature did address police-frequency equipment, and the way it drew the line is the clearest evidence that detectors are outside it. P.L.1991, c.432 created three sections. N.J.S.A. 2C:33-21 makes it a crime of the fourth degree to intercept a police, fire or emergency medical transmission and use the information to facilitate a crime or in a way that interferes with police, firefighting or ambulance operations. N.J.S.A. 2C:33-22 makes it a crime of the fourth degree to possess or control a radio capable of receiving those transmissions while committing or attempting a crime, including immediate flight. Then N.J.S.A. 2C:33-23 says the term "police, fire or emergency medical communications system" in that act "shall not include radar devices used to monitor vehicular speed." A radar detector receives the emitted beam of a speed-measuring unit, not a voice channel, and the Legislature took it out of the scheme by name.

Nothing else in the New Jersey statutes fills the gap. The word "radar" appears in only seven sections of the entire code, and outside 2C:33-23 the only motor vehicle use of it is R.S. 39:4-103.1, which points at the police rather than the driver. Enacted as L.1992, c.91, it provides that "a law enforcement officer or agency shall not use photo radar to enforce the provisions of chapter 4 of Title 39," and defines photo radar as a radar unit linked to a camera that automatically photographs a speeding vehicle. New Jersey therefore has no automated speed cameras issuing tickets in the mail. Speed enforcement here is an officer with a hand-held or vehicle-mounted radar or lidar unit, working live at the roadside, which is exactly the enforcement style a detector is built to notice.

Mounting is the New Jersey constraint that actually catches drivers. R.S. 39:3-74 provides that no person shall drive with "any sign, poster, sticker or other non-transparent material upon the front windshield, wings, deflectors, side shields, corner lights adjoining windshield or front side windows," with an exception only for a certificate or article the State requires you to display. A detector suction-cupped to the glass is opaque material on the front windshield. The same section separately forbids driving a vehicle "so constructed, equipped or loaded as to unduly interfere with the driver's vision to the front and to the sides," which reaches a unit and its cable however it is fixed. A dashboard cradle, a vent mount or a visor clip keeps the device off the glass and out of that language.

Commercial drivers are in a different position entirely, and it is federal law that puts them there rather than anything in Title 39. 49 C.F.R. 392.71(a) provides that "No driver shall use a radar detector in a commercial motor vehicle, or operate a commercial motor vehicle that is equipped with or contains any radar detector," and paragraph (b) forbids a motor carrier from requiring or permitting a driver to do so. Mere presence in the cab is enough; the rule reaches a vehicle that "contains" a detector, switched off or not.

One more New Jersey fact matters for anyone who assumes equipment gets screened somewhere. It does not. N.J.S.A. 39:8-1(a), amended by L.2010, c.29, provides that passenger automobiles and noncommercial trucks "shall only be inspected for emissions and emission-related items such as emission control equipment and on-board diagnostics." A New Jersey inspection station never looks at a detector, a mount or anything else on the dash.

Owning or using a radar detector in a private New Jersey vehicle carries no penalty, because no section of the New Jersey statutes creates one. S. 39:3-74 for the mount rather than the device. A. 39:3-86 supplies it: not less than $25 and not more than $500, or imprisonment for up to fifteen days, or both. A. S. 39:4-98. The scanner offences sit at a different level of seriousness. A. A. A. 2C:33-23 removes those devices from the definition. For a commercial driver, a detector in the cab is an out-of-service and enforcement matter under the federal motor carrier rules rather than a Title 39 summons.