Is anonymous tip enough to justify pulling over drunken driver? |

Is anonymous tip enough to justify pulling over drunken driver?

Jim Porter

A driver in Mendocino County called on her cell phone (hopefully hands-free) reporting that “a Silver Ford 150 pickup license plate number 8-David94925 had run me off the road” and was last seen on southbound Highway 1 at mile marker 88.


Is that anonymous cell phone tip legally adequate “reasonable suspicion” for a CHP “investigative stop” of the driver, with no other corroborating evidence, like the officer’s observation of the Ford 150 driving erratically?

The U.S. Supreme Court took up the question.


Those were the facts on August 23, 2008 when CHP officers pulled over the Ford 150, found 30 pounds of marijuana in the truck bed and arrested Lorenzo and Jose Navarette.

Getting ahead of the story, the Navarettes pled guilty to transporting marijuana and were sentenced to 90 days in jail plus three years of probation.

The minimal penalty alone tells the story of how marijuana has become accepted in our culture, especially in Mendocino County where it is the culture.


The Fourth Amendment of the U.S. Constitution permits brief investigative stops, such as the traffic stop in this case, when there is a “reasonable suspicion” of criminal activity.

The standard takes into account “the totality of the circumstances – the whole picture.” A mere “hunch” does not create reasonable suspicion … the level of suspicion required is “considerably less than proof of wrongdoing by preponderance of the evidence,” and “obviously less than is necessary for probable cause.” (Only lawyers and judges could make sense of that standard.)

The Supreme Court pointed out that “an anonymous tip alone seldom demonstrates the informant’s basis of knowledge or veracity. . . because an anonymous tipster’s veracity is largely unknown and unknowable.”

Was the “run me off the road” tip sufficiently reliable to justify a stop of the pickup? Does your answer change if you knew the CHP officers followed the pickup for five minutes and noticed no erratic driving?


A majority of the Supreme Court concluded that even though the tipster was anonymous, she had sufficient first-hand knowledge and promptly reported the incident in detail, suggesting the tip was reliable.

More reliable than a tipster’s mere allegation of “a drunk driver.” Point being, if you report a drunk driver, give the details.


A mixed bag of conservative and liberal justices dissented. Justice Scalia wrote that the majority opinion served up a “freedom destroying cocktail,” concluding with this paragraph: “Drunken driving is a serious matter, but so is the loss of our freedom to come and go as we please without police interference … after today’s opinion all of us on the road, and not just drug dealers, are at risk of having our freedom of movement curtailed on suspicion of drunkenness, based upon a phone tip, true or false, of a single instance of careless driving.”


Quite a few of you commented that while “’Mrs. P’ (whoever she is),” is a wonderful person, she was GUILTY of texting while driving for looking at a cell phone message. Off to jail she goes! Will be quiet around the house.

Jim Porter is an attorney with Porter Simon licensed in California and Nevada, with offices in Truckee, Tahoe City and Reno. Jim’s practice areas include: real estate, development, construction, business, HOAs, contracts, personal injury, mediation and other transactional matters. He may be reached at or

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