Law enforcement properly pulled over a vehicle for not signalling before its tires crossed the lane divider, the Supreme Court ruled on Monday, making the seizure of drugs from the truck permissible under the Fourth Amendment.

Colorado State Patrol Trooper Christian Bollen began following a pickup truck driving on Interstate 70 in Mesa County after computer databases told him that it was a rental registered in Nevada that recently appeared in Texas. He saw on two occasions that the truck’s tires were “on top of the center dividing line” when the driver, Aldo Gabriel Gutierrez, activated the turn signal.

Bollen pulled the truck over and, while interrogating Gutierrez, became suspicious that he and his passenger were transporting narcotics. Gutierrez agreed to let Bollen search the truck, whereupon the trooper found five pounds of heroin.

Gutierrez and his passenger, Julio Cesar Carrillo-Toledo, asked the trial court to suppress the evidence of the seized drugs, alleging that Bollen violated their Fourth Amendment protection against unreasonable searches when he had no reasonable basis to pull them over. The court agreed, concluding that Gutierrez had not violated the lane-change law, despite the trooper’s belief to the contrary.

Gutierrez and Carrillo-Toledo appealed to the Colorado Court of Appeals, which transferred the matter directly to the Supreme Court. The justices agreed that a traffic stop triggers Fourth Amendment protections, meaning that an officer needs a “reasonable suspicion of criminal activity.”

Colorado law requires a “signal of intention to turn right or left…be given continuously for at least two hundred feet on all four-lane highways and other highways where the prima facie or posted speed limit is more than forty miles per hour.”

The trial court judge interpreted the law to mean that a driver can have his or her wheels on the lane divider when signalling, as long as the “intention” is communicated.

Justice William W. Hood III quoted the dictionary definition of “intention” as something indicating future action, therefore determining that the lower court judge misinterpreted the law.

“The driver must signal to show that he plans to change lanes. In short, the signal must precede any movement between lanes,” Hood wrote in the court’s opinion. The trooper also testified that in one of the lane change violations, the truck’s tires were partially in the other lane when Gutierrez activated the turn signal. Because the trial court did not question the accuracy of that testimony, the justices had no choice but to defer to the record.

The court concluded that the traffic stop did not create a Fourth Amendment violation, reversing the prior ruling. The cases are People v. Gutierrez and People v. Carrillo-Toledo.