Police roadblocks intended to detect drunken drivers may be established in Maryland, under a plan submittted to the superintendent of Maryland State Police yesterday.

Under the roadblock plan, troopers on selected state highways would stop motorists suspected of driving under the influence of alcohol and test them for drunkenness.

Col. Thomas S. Smith, who was given the proposal by his field operations division, said that he approves of using roadblocks to catch drunken drivers, but will study the plan to determine its legality.

The so-called "sobriety checkpoints" have been in operation in Montgomery County since last October. A challenge to the constitutionality of the roadblocks, brought in Circuit Court by a motorist, was overruled by Judge John J. Mitchell earlier this month when he ruled that the roadblocks did not violate the motorist's constitutional rights.

But the American Civil Liberties Union has continued its opposition to the practice. "We believe the sobriety roadblocks are a serious threat to personal freedoms guaranteed in the constitution," said Arthur Spitzer, legal director of the Washington-area American Civil Liberties Union. "If police can stop people to see if they're drunk, what is there to stop them from setting up roadblocks to see if people are carrying some kind of weapon?"

Dan McCarthy, a state police spokesman, said that the roadblocks, if imposed, would be limited.

"Col. Smith has said he would prefer the 'Band-Aid' approach to using the roadblocks," McCarthy said. "The roadblocks would only be used on highways which have had high incidents of alcohol-related fatalities and conventional enforcement has not been effective."

Under the proposal submitted to Smith, state police would be authorized only to stop motorists who showed signs of being under the influence of alcohol, McCarthy said.

In the last year, drunk driving arrests have nearly doubled in Maryland. State police have set enforcement of drunk driving laws as its top priority.