It is absurd to think a police officer can look at a car on the highway and know its speed with enough precision to perform a traffic stop, the Fourth Circuit US Court of Appeals ruled Tuesday. Deputy James Elliott had pulled over motorist Sean C. Sowards by looking and guessing that it was traveling 75 MPH on Interstate 77 in North Carolina, where the speed limit is 70 MPH. Elliott had a radar gun in his patrol car, but he did not use it.

At trial, Elliott testified his certification to use radar in the state included a visual speed estimation test. He admitted one of his estimates was off by 12 MPH, but he still passed the course.

"There's not really a technique," Elliott explained in court. "I've been measuring speeds all my life.... There's no guessing about it. It's an estimation based on tracking history and my training and experience."

The deputy tripped up when the prosecutor asked Elliott how far away Sowards's vehicle had been when Elliott began that tracking history. Elliott testified he saw the car 100 yards away.

Prosecutor:

And how many feet are in a hundred yards?

Elliott:

There's 12 feet in a yard.

Prosecutor:

So 300 feet?

Elliott:

Correct.

Judge:

How many feet are in a yard?

Elliott:

How many feet? There's 12 feet in a yard.

Court:

Well, do you know what a yardstick is?

Elliott:

Yes, sir.

Court:

How many inches in a yardstick?

Elliott:

Well, on a yardstick there's 12 inches. Well, it depends on the yard stick that . . . you have.

Elliott went on to insist that he could estimate a car's speed without needing to estimate the distance it traveled. After hearing the case, a lower court refused to throw out the traffic stop as invalid.

"Officer Elliott had probable cause to believe a traffic violation had occurred based on speed," US District Court Judge Richard L. Voorhees ruled. "He's trained to estimate speeds. His difficulty with measurements is immaterial to his estimate of speed as that did not depend on time or distance."

As a result, Sowards was convicted for possession of the drugs that were uncovered as a result of the traffic stop. Though he has already served his time in prison for this case, he appealed on the grounds that the traffic stop itself had been illegal. The appellate panel majority agreed.

"It was clear error for the district court to find that Deputy Elliott's 'difficulty with measurements is immaterial to his estimate of speed as that did not depend on time or distance,'" Judge James A. Wynn, Jr. wrote for the majority. "This finding rings absurd because one cannot discern the speed of a vehicle measured in miles-per-hour without discerning both the increment of distance traveled and the increment of time passed."

The Fourth Amendment requires reasonable suspicion, a standard not met with a guess regarding the slight excess in speed claimed. To find otherwise, the majority argued, would be to allow police to pull anyone over for any reason, since the courts already overlook subjective motivations of officers.

"In the absence of sufficient additional indicia of reliability, an officer's visual approximation that a vehicle is traveling in slight excess of the legal speed limit is a guess that is merely conclusory and which lacks the necessary factual foundation to provide an officer with reasonably trustworthy information to initiate a traffic stop," Wynn wrote.

The court also noted that an Ohio Supreme Court decision that had upheld the use of visual speed estimation was swiftly overturned by the state legislature.

A copy of the decision is available in a 350k PDF file at the source link below.