An off-duty MTA employee was arrested for drunk driving Sunday after he took a city bus for a booze cruise on Long Island, police said.

Bus operator Alexander Copeland, 52, was pulled over by state police about 2:20 p.m. after several worried commuters phoned authorities about an erratic NYC transit bus swerving along the Northern State Parkway in Westbury, according to state police.

Copeland, who reeked of booze, was given a sobriety test that determined his blood-alcohol level was .20 percent, more than double the legal limit.

In addition to a DWI, the blitzed bus driver was hit with charges of reckless endangerment and the unauthorized use of a vehicle without owner’s consent.