Mexican truckers seeking to drive their cargo across the United States cleared a last hurdle Tuesday when the Senate gave final approval to a compromise with President Bush on safety requirements.

The 97-2 vote for the $59.6 billion annual transportation spending bill enables the government to begin instituting a new federal screening system on trucks entering the southern United States.

The new rules call for safety examinations of Mexican trucking companies and their vehicles, driver's license verification, and other checks to be performed by U.S. inspectors.

U.S. inspectors are to inspect half of all Mexican trucking companies that have four or more trucks wishing to enter the United States. Truck scales must be installed at the 10 busiest border crossings within a year.

The president's goal of allowing the trucks on American soil beginning Jan. 1 will be set back by months while the safety measures are put in place.

Until the rules are implemented, Mexican vehicles will be allowed to continue operating in a roughly 20-mile-wide zone north of the country's border.

Bush had threatened to veto the transportation bill if the two sides could not come to an agreement on the Mexican trucking issue. Instead, his signature ends a battle between unions and safety groups that are trying to prevent lost trucking jobs in the United States by claiming Mexican trucks are less safe than American lorries and business groups that want to reduce the costs of transferring goods from Mexican to U.S. trucks when they cross the border.

Other features of the transportation bill, which totaled $1.5 billion more than last year, includes hundreds of millions of dollars for road-building and other transportation projects in lawmakers' home districts. 

Sen. John McCain, R-Ariz., who supported White House efforts against tougher rules, praised the agreement but voted against the bill because he said it added too much extra spending for lawmakers' pet projects.

Among those projects are $4.5 million for buses in Kentucky, home state of GOP Rep. Harold Rogers, who chairs the House Appropriations Committee's transportation subcommittee; and $4.5 million for bridge construction in Yakima, Wash., home state of Murray, who chairs the Appropriations transportation subcommittee in the Senate.

Sen. Evan Bayh, D-Ind., also opposed the bill.  The House approved the legislation by 371-11 last Friday.

The Associated Press contributed to this report.