Idaho's Supreme Court has struck down as unconstitutional the use of police roadblocks to catch drunken drivers.

The 3-2 decision, written by Justice Robert Huntley, found the roadblocks violated the state constitution's ban on unreasonable search and seizure."In light of the individual's right of freedom from arbitrary governmental intrusion and the questionable efficacy of roadblocks, we conclude that such roadblocks cannot withstand constitutional scrutiny," Huntley wrote.

The decision came on an appeal by David Henderson, one of 11 motorists picked up for drunken driving during a two-hour roadblock operated by Boise police on Memorial Day weekend in 1985.

All motorists approaching the roadblock were briefly stopped for evidence of intoxication.

Huntley also said there was no authority for stopping motorists without evidence of criminal wrongdoing.

"A citizen is free to stroll the streets, hike the mountains and float the rivers of this state without interference from the government," Huntley wrote. "That is, police treat you as a criminal only if your actions correspond."

Acting Justice Jesse Walters dissented, supported by Justice Robert Bakes.

He said the need to prevent alcohol-related accidents by deterring drunken driving "outweighs the minimal intrusion" imposed on motorists.

"The scales tip in favor of the public welfare," he wrote, "and hence justify the systematic, nondiscretionary and brief stop to check the sobriety of the driver."