Police found about 100 pounds of marijuana when they pulled over Chettero for crossing a fog line, which marks the legal limit of a road surface. Chettero says he didn't cross the line, and that troopers violated his right to travel.
State attorney Jeffrey Gray acknowledged that Utah Highway Patrol troopers pulled over more out-of-state cars during the sting operation that netted Chettero, but said it was a legitimate investigative technique used during the harvest season, when investigators believed people would be transporting more product east from California.
"Law enforcement enjoys wide latitude in setting enforcement priorities and also allocating their resources accordingly," he said. "Chettero is evidence of the fruits of what they do."
From Nov. 14 to 16 of 2008, troopers pulled over 147 drivers between Kimball Junction and the Wyoming border. All but one were from out of state, according to court documents. The UHP didn't offer any empirical evidence that out-of-state drivers are more likely to be carrying pot, and Justice Christine Durham pressed Gray on whether it's really fair to target them.
"Even the existence of a harvest doesn't get you that kind of statistical information or empirical evidence," she said. "We don't want unbridled discretion in law enforcement because they have so much power."
D'Elia argued the traffic stops send a message that people from out of state aren't welcome, but Justice Thomas Lee didn't appear convinced.
"I would take it as a different message: You better not bring marijuana through the state of Utah, which is the right message for law enforcement to send," he said.
Chettero pleaded guilty to a felony charge of possession with intent to distribute last year and was sentenced to 18 months probation.
Gray, meanwhile, argued that the stops were made during a specific operation by a specialized unit. If the high court were to decide in Chettero's favor, it could call into question other specialized investigative techniques, like those used by local police department's gang units, he said.
"I think it would have a substantial impact," he said. "This is what law enforcement does."
A lower court found the troopers had treated out-of-state drivers differently, but ruled that didn't violate the drivers' right to travel as long as the trooper had a good reason for pulling them over. D'Elia asked the high court to overturn the second portion and reverse the conviction. The justices took the case under advisement. No date was immediately set for the court's decision.