The Montana Supreme Court recently affirmed the legality of a traffic stop initiated by a law enforcement officer who relied on a roadside RADAR sign to determine a driver’s speed. The case, State v. Flynn1, centered on whether the officer had particularized suspicion to stop the defendant driver.
Background of the Case
On a late evening in November 2020, the arresting officer observed defendant’s vehicle overtaking another car at what appeared to be a high rate of speed on Benton Avenue in Helena. The posted speed limit was 25 mph. Positioned near a RADAR-controlled traffic sign—a device that displays passing vehicles’ speeds—the noted that the sign registered defendant’s speed at 36 mph.
Relying on her training, experience, and the speed indicated by the RADAR sign, the officer initiated a traffic stop. During the stop, she observed signs of impairment, leading to defendant’s arrest for DUI.
Defendant’s Argument: Challenging the Use of RADAR Signs
Defendant filed a motion to suppress the evidence obtained from the traffic stop, arguing that the officer lacked particularized suspicion to stop him. Specifically, he contended that the RADAR sign constituted an “automated enforcement system” prohibited under Montana law. § 61-8-206(2)(a), MCA. Defendant did not contend the RADAR sign was unreliable.
Montana Law on Automated Enforcement Systems
Montana Code Annotated § 61-8-206(2)(a) states that local authorities may not use an “automated enforcement system designed to detect traffic violations . . . to enforce traffic laws.” Defendant argued that because the RADAR sign detects and displays drivers’ speeds, it falls under this prohibition.
The Court’s Analysis and Decision
The Montana Supreme Court rejected the defendant’s arguments, affirming the lower courts’ decisions. The Court’s key points included:
- Particularized Suspicion Established: the officer’s observation of the defendant overtaking another vehicle at a high speed, combined with her professional training and experience in estimating vehicle speeds, on their own provided sufficient particularized suspicion for the stop.
- RADAR Sign as a Supplementary Tool: The RADAR sign served to confirm the officer’s estimation but was not the sole basis for the stop, nor was it necessary to legally stop the defendant. The Court noted that peace officers are permitted to use various tools to aid in enforcing traffic laws, including RADAR devices.
- RADAR Sign Not an Automated Enforcement System: The Court clarified that the RADAR sign did not qualify as an “automated enforcement system” as prohibited by Section 61-8-206(2)(a). Unlike red-light cameras or speed cameras that automatically issue citations without direct officer involvement, the RADAR sign merely displays vehicle speeds to drivers and does not enforce the law by itself.
Implications of the Decision
This ruling has implications for both law enforcement practices and drivers in Montana:
- For Law Enforcement: Officers can confidently use RADAR signs as one of several tools to establish particularized suspicion for traffic stops, provided they also rely on their training and observations, and subject to any defense challenges regarding the reliability of the RADAR sign.
- For Drivers: Motorists should be aware that exceeding the speed limit in areas monitored by RADAR signs can lead to lawful traffic stops.
If you have questions about traffic stops or DUI charges, it’s crucial to consult with a knowledgeable attorney who can provide guidance based on the most recent legal developments. Contact me today for a free consultation.
*Disclaimer: the above is for informational purposes only and does not constitute legal advice.
- State v. Flynn, 2024 MT 236. ↩︎