When it comes to DUI / OUI roadblocks, aka “sobriety checkpoints”, Massachusetts law permits police to establish DUI roadblocks so long as the selection of vehicles stopped is not arbitrary and the procedure is conducted pursuant to a plan devised by law enforcement supervisors.
By way of background, a stop of a car at a police roadblock, no matter how brief, is considered to be a warrantless seizure that implications constitutional protections under the Fourth Amendment to the United States Constitution and Article 14 of the Massachusetts Declaration of Rights. The United States Supreme Court has upheld police using DUI checkpoints if they are reasonable and balance the public interest in reducing alcohol related accidents against a person’s constitutional rights.
The reason police must operate an OUI checkpoint according to a devised plan is because it is illegal for police to target which vehicles to stop. Even fixed checkpoints where police stop cars according to no set plan or pattern are illegal. In other words, if the police officers have any discretion in the stopping of vehicles, the constitutionality of the sobriety checkpoint will not be upheld.