A federal judge blocked a federal plan to require random drug testing of 3 million interstate drivers nationwide but did allow pre-employment and post-accident testing.

U.S. District Judge Marilyn Hall Patel issued a temporary restraining order against random drug testing of truckers and interstate bus drivers. She told government lawyers she wanted to review how widespread substance abuse is in the trucking industry before a future hearing.The material in the Federal Register in support of testing amounted to nothing more than "a well-taken diatribe against drug abuse in American society," Patel said.

The program was to start Wednesday, but the Transportation Department did not require companies to conduct any actual testing until next December, according to department spokesman Bob Marks.

More than 1 million other private employees in the rail, airline and maritime industries are scheduled to begin random testing.

The order expires Dec. 30, when Patel is scheduled to hear arguments on a longer-lasting injunction against all testing programs affecting truckers and interstate bus drivers.

Marks declined to comment on Patel's ruling, saying the government would present its side on Dec. 30.

Jeffrey King, lawyer for the Owner-Operator Independent Drivers Association of America, which challenged the testing program, said drug abuse among truckers "is probably below the national average."