Radar Detectors in North Dakota: Legal in a Private Car, Banned in a Commercial Vehicle

Proving this negative properly means showing what the code does contain. The only radar provision in title 39 is section 39-03-15, Radar evidence in speed violations, and it points the other way: it authorizes the state to use the technology rather than restricting a driver's response to it. The section provides that the speed of any motor vehicle may be checked by the use of radio microwaves or other electrical device, that the results are accepted as prima facie evidence of speed in any court or legal proceeding, and that a driver may be arrested without a warrant provided the arresting officer is in uniform or displays the officer's badge of authority and either observed the recorded speed personally or received a radio message from the officer who did. Its closing sentence preserves the power of cities and towns to adopt and use such devices. Nothing in it, or anywhere else in the Century Code, addresses a device that receives those emissions.

Section 39-21-46(4) is the general permission that fills the gap. It states that nothing contained in chapter 39-21 may be construed to prohibit the use of additional parts and accessories on any vehicle not inconsistent with the provisions of the chapter. Chapter 39-21 is North Dakota's exhaustive equipment chapter, running from lighting through brakes, mirrors, glazing, mufflers and modification limits, and a detector conflicts with none of it. The Century Code likewise contains no provision on a jammer or any device that interferes with speed measurement, so state law is silent on that too rather than permissive by design.

The commercial exception comes in through the subsection immediately above. Section 39-21-46(3) requires the superintendent of the state highway patrol to adopt rules under chapter 28-32 concerning the safe operation of motor vehicles and the conduct of motor carrier audits and inspections, and requires those rules to duplicate or be consistent with current motor carrier safety regulations of the United States Department of Transportation. The superintendent may adopt them by reference, and any such adoption is construed to incorporate amendments made from time to time. The federal rule brought in that way is 49 C.F.R. § 392.71, which 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 that no motor carrier shall require or permit a driver to violate it. So the prohibition a North Dakota trucker faces is real, it is enforced by the Highway Patrol, and it reaches mere possession in the cab rather than only use.

Where the Century Code does bite on a private driver is the mounting, not the device. Section 39-21-39(4) reaches any object displayed, affixed or applied on the front windshield or any window, and requires the object in conjunction with that glass to leave a light transmittance of at least seventy percent on the windshield or thirty-five percent on any other window. A suction-cup detector on the windshield is such an object, and an opaque housing cannot meet seventy percent. Section 39-21-39(1) is a second, independent limit: it bars driving with any sign, poster or other nontransparent material on the front windshield, side wings, or side or rear windows which obstructs the driver's clear view of the highway or any intersecting highway. Mounting on the dashboard, on a vent, or behind the mirror head avoids both, and the AS-1 and top-five-inch allowance in section 39-21-39(5) does not help here because it is written for nonreflective sunscreening or tinting material rather than for objects.

One practical note about the detection itself. Because section 39-03-15 lets an officer arrest without a warrant on a radio relay of another officer's reading, a detector that alerts on the transmitting unit gives no warning of the officer who receives the message and makes the stop.

There is no North Dakota offense of possessing or using a radar detector in a private vehicle, so there is no fee, no points entry and nothing to contest. A commercial driver is in a different position: a violation of the motor carrier safety rules the Highway Patrol adopts under section 39-21-46(3), which include the federal radar detector prohibition, is expressly made a noncriminal violation by that subsection and draws the fee set by section 39-06.1-06, which for all other violations of those rules is $50 under section 39-06.1-06(5)(d). Section 39-06.1-07(1) allows a notification form separate from the uniform traffic summons for a section 39-21-46(3) charge. A mounting that blocks the windshield is charged instead under section 39-21-39, a $20 statutory fee under section 39-06.1-06, with 2 points under section 39-06.1-10(3)(a)(9) where the driver knowingly drove with unlawful equipment in violation of section 39-21-46.