In Navarette v. California [i] the United States Supreme Court examined the validity of a vehicle stop based upon an anonymous 911 caller’s report that the vehicle in question had just run the caller off the road.    The issue before the Court was whether or not the anonymous call in this case amounted to reasonable suspicion which would justify a stop.

It is noted that this case is a midway point between Alabama v. White where an anonymous informant gave detailed information concerning Ms. White’s future activities with respect to the sale of drugs which law enforcement was able to corroborate before making the stop and Florida v. J.L. where the anonymous caller merely provided the description of J.L. and his location and the fact that he was in possession of a firearm.  The Court concluded that the stop of White was justified because the informant provided detailed information regarding future conduct which law enforcement corroborated before the stop, while the stop of J.L. was no good because anyone could make a phony call providing description and location.

The Court outlined the facts as follows:

On August 23, 2008, a Mendocino County 911 dispatch team for the California Highway Patrol(CHP) received a call from another CHP dispatcher in neighboring Humboldt County. The Humboldt County dispatcher relayed a tip from a 911 caller, which the Mendocino County team recorded as follows: “‘Showing southbound Highway 1 at mile marker 88, Silver Ford 150 pickup. Plate of 8-David-94925. Ran the reporting party off the roadway and was last seen approximately five [minutes] ago.’” The Mendocino County team then broadcast that information to CHP officers at 3:47 p.m.

A CHP officer heading northbound toward the reported vehicle responded to the broadcast. At 4:00 p.m., the officer passed the truck near mile marker 69. At about 4:05 p.m., after making a U-turn, he pulled the truck over. A second officer, who had separately responded to the broadcast, also arrived on the scene. As the two officers approached the truck, they smelled marijuana. A search of the truck bed revealed 30 pounds of marijuana. The officers arrested the driver, petitioner Lorenzo Prado Navarette, and the passenger, petitioner José Prado Navarette.

Petitioners moved to suppress the evidence, arguing that the traffic stop violated the Fourth Amendment because the officer lacked reasonable suspicion of criminal activity.  

It is noted that the question at issue is when does an anonymous tip amount to reasonable suspicion and what factors can an officer look to in determining when reasonable suspicion exists. The Court noted that prosecutor did not introduce the recording of the call nor the dispatcher or caller at the suppression hearing notwithstanding the fact that the caller in this case had identified herself, thus the information was treated as anonymous tip throughout this case.  It can be concluded that if the caller, the dispatcher, or the recording, had been introduced by the prosecutor, it is unlikely that this case would have ever been heard by the Court.

In its analysis the Court wrote:

The Fourth Amendment permits brief investigative stops—such as the traffic stop in this case—when a law enforcement officer has “a particularized and objective basis for suspecting the particular person stopped of criminal activity.”  The “reasonable suspicion” necessary to justify such a stop “is dependent upon both the content of information possessed by police and its degree of reliability.” The standard takes into account “the totality of the circumstances—the whole picture. Although a mere “‘hunch’” does not create reasonable suspicion,  the level of suspicion the standard requires is “considerably less than proof of wrongdoing by a preponderance of the evidence,” and “obviously less” than is necessary for probable cause. 

These principles apply with full force to investigative stops based on information from anonymous tips. We have firmly rejected the argument “that reasonable cause for a[n investigative stop] can only be based on the officer’s personal observation, rather than on information supplied by another person.” Of course, “an anonymous tip alone seldom demonstrates the informant’s basis of knowledge or veracity.” That is because “ordinary citizens generally do not provide extensive recitations of the basis of their everyday observations,” and an anonymous tipster’s veracity is “‘by hypothesis largely unknown, and unknowable.’” Ibid. But under appropriate circumstances, an anonymous tip can demonstrate “sufficient indicia of reliability to provide reasonable suspicion to make [an] investigatory stop.”

Applying the rules governing anonymous tips to the facts of this case the Court noted:

The initial question in this case is whether the 911 call was sufficiently reliable to credit the allegation that petitioners’ truck “ran the [caller] off the roadway.” Even assuming for present purposes that the 911 call was anonymous, see n. 1, supra, we conclude that the call bore adequate indicia of reliability for the officer to credit the caller’s account. The officer was therefore justified in proceeding from the premise that the truck had, in fact, caused the caller’s car to be dangerously diverted from the highway.

By reporting that she had been run off the road by a specific vehicle—a silver Ford F-150 pickup, license plate 8D94925—the caller necessarily claimed eyewitness  knowledge of the alleged dangerous driving. That basis of knowledge lends significant support to the tip’s reliability. An informant’s] explicit and detailed description of alleged wrongdoing, along with a statement that the event was observed firsthand, entitles his tip to greater weight than might otherwise be the case. A driver’s claim that another vehicle ran her off the road, however, necessarily implies that the informant knows the other car was driven dangerously.

There is also reason to think that the 911 caller in this case was telling the truth. Police confirmed the truck’s location near mile marker 69 (roughly 19 highway miles south of the location reported in the 911 call) at 4:00 p.m. (roughly 18 minutes after the 911 call). That timeline of events suggests that the caller reported the incident soon after she was run off the road. That sort of contemporaneous report has long been treated as especially reliable. In evidence law, we generally credit the proposition that statements about an event and made soon after perceiving that event are especially trustworthy because substantial contemporaneity of event and statement negate the likelihood of deliberate or conscious misrepresentation.”  Another indicator of veracity is the caller’s use of the 911 emergency system.  A 911 call has some features that allow for identifying and tracing callers, and thus provide some safeguards against making false reports with immunity.

It is noted that all of the Court’s assertions above related to the reliability of the tip, the Court then pointed out that a reliable tip does not justify a stop unless the reliable tip amounts to reasonable suspicion to believe that criminal activity is afoot.  Thus, the Court then turned to analyze whether the tip that a truck had just ran another motorist off the road was a sufficient basis to establish reasonable suspicion to believe criminal activity, such as impaired driving was occurring.  The Court noted that certain driving behaviors would lead a reasonable officer to believe that impaired driving was occurring.  The Court went on to assert that a reliable tip of dangerous driving behavior would support reasonable suspicion of impaired driving.

The Court wrote:

Running another vehicle off the road suggests lane-positioning problems, decreased vigilance, impaired judgment, or some combination of those recognized drunk driving cues. See Visual Detection of DWI Motorists 4-5. And the experience of many officers suggests that a driver who almost strikes a vehicle or another object—the exact scenario that ordinarily causes “running [another vehicle] off the roadway”—is likely intoxicated. As a result, we cannot say that the officer acted unreasonably under these circumstances in stopping a driver whose alleged conduct was a significant indicator of drunk driving.

The Court noted that:

Reasonable suspicion “need not rule out the possibility of innocent conduct.

Finally, the officer’s failure to observe additional suspicious conduct during the short period that he followed the truck did not dispel the reasonable suspicion of drunk driving, and the officer was not required to surveil the truck for a longer period.

The majority (5-4 decision) noted that this case was a close call.  In writing for the dissent, Justice Scalia outlined his concern that officers would take the majority decision to stand for the proposition that officers will believe that reasonable suspicion with respect to a vehicle stop exists anytime they have an anonymous report of careless driving behavior.

Bottom Line:
Anonymous reports may support reasonable suspicion to make a vehicle stop however two essential components must be met:

  • The anonymous report must have some indicia of reliability going beyond simply describing location and description.

The reliable anonymous information must add up to reasonable suspicion to believe that criminal activity is afoot.


Note:  Court holdings can vary significantly between jurisdictions.  As such, it is advisable to seek the advice of a local prosecutor or legal adviser regarding questions on specific cases.  This article is not intended to constitute legal advice on a specific case.



[i] Navarette v. California, ___U.S.___, 2014 U.S. LEXIS 2930 (2014).

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