Transportation Secretary Norman Mineta said April 30 federal inspectors were preparing to inspect Mexican trucks this summer if the Supreme Court ruled the trucks can operate beyond U.S. commercial zones, the Fort Worth Star-Telegram reported.

"We may see a decision as early as June," Mineta said in a speech. "If we get the green light, but Bush administration is prepared to act, and hundreds of inspectors are standing by."

President Bush opened all U.S. roads to truck traffic from Mexico in 2002, but the move was stalled by legal challenges. Critics say the trucks may harm the environment and highway safety.