Radar Detectors Are Legal in Texas Cars, Jammers Are a Class C Misdemeanor

Chapter 547 of the Transportation Code is where Texas writes down what a vehicle may and may not be equipped with, and Section 547.004(a)(3) makes it a misdemeanor to operate a vehicle that is equipped in a manner prohibited by that chapter. If Texas banned radar detectors, the ban would sit there. The chapter reaches radar exactly once, in Section 547.616, which the Legislature added by Acts 2011, 82nd Leg., R.S., Ch. 739 (H.B. 1116), effective September 1, 2011, and that section is about jamming rather than detecting.

The definition does the work. A radar interference device is one designed, manufactured, used or intended to be used to interfere with, scramble, disrupt or otherwise cause to malfunction a radar or laser device used to measure the speed of a motor vehicle by a law enforcement agency of this state or a political subdivision of this state, and the section names the products it has in mind: a radar jamming device, a jammer, a scrambler or a diffuser. Every verb in that list describes active interference with the police instrument. A passive detector receives the signal the police unit is already emitting and does nothing to it. The Legislature also wrote a carve-out saying the term does not include a ham radio, band radio or similar electronic device, which shows it was thinking about receivers and chose to leave ordinary radio gear alone.

The prohibitions run wider than driving. Subsection (b) bars using, attempting to use, installing, operating or attempting to operate an interference device in a motor vehicle the person operates, and exempts a law enforcement officer in the discharge of the officer's official duties. Subsection (c) reaches the retail side: a person may not purchase, sell or offer for sale an interference device to be used in that way. Texas therefore criminalizes the jammer trade while leaving the detector trade untouched, which is why detectors sit openly on shelves in Texas electronics stores.

Commercial drivers get the opposite answer. The federal rule at 49 C.F.R. Section 392.71(a) says 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 subsection (b) bars a motor carrier from requiring or permitting a driver to do so. Texas reaches that rule through Transportation Code Chapter 644: Section 644.051(a) directs the public safety director to adopt rules regulating the safe operation of commercial motor vehicles, subsection (b) requires those rules to be consistent with federal safety regulations, and subsection (c) permits the director to adopt all or part of the federal safety regulations by reference. Section 644.052(a) then makes a rule adopted under the chapter apply uniformly throughout Texas, notwithstanding federal exemptions other than the intracity and commercial zone exemption in 49 C.F.R. Part 395. For this purpose Section 644.001(1) defines a commercial motor vehicle as one within 49 C.F.R. Section 390.5 if operated interstate, or within Transportation Code Section 548.001 if operated intrastate.

Mounting is the limit most Texas drivers actually run into. Section 547.613(a)(1) makes it a misdemeanor to operate a motor vehicle that has an object or material placed on or attached to the windshield or a side or rear window that obstructs or reduces the operator's clear view. The list of exceptions in Section 547.613(b) covers a rearview mirror, an adjustable nontransparent sun visor mounted in front of a side window and not attached to the glass, a rear window wiper motor, a luggage rack attached to the rear trunk and a window carrying a certificate required by law, but it names nothing resembling a detector. A suction cup on the windshield is therefore judged case by case against the clear-view test, while a visor clip or a dash pad mount is outside Section 547.613 altogether because nothing is attached to the glass.

What Texas does not do is worth stating plainly. There is no registration requirement for a detector, no permit, no possession offense, no restriction tied to the driver's age or license class, and no separate rule for a rental or leased vehicle. The only status that changes the answer is driving a commercial motor vehicle.

23 punishes by a fine not to exceed $500 with no jail term. Buying, selling or offering one for sale carries the same classification under subsection (c), so a Texas retailer faces the same exposure as the driver. 153 lets the Department of Public Safety add an administrative penalty that may not exceed the maximum provided for a violation of a similar federal safety regulation. 152 applies to refusing an authorized inspection, not to the detector itself. 004(c) lets the court dismiss it if the driver removes the obstruction before the first court appearance and pays a reimbursement fee not to exceed $10. 004(d) withholds that dismissal route from commercial motor vehicles.