WASHINGTON — Mexican buses and trucks operated by Mexican drivers would be permitted to cross into and travel through the United States under an agreement reached March 3 between President Obama and Mexican President Felipe Calderon.

Congress, however, must approve the agreement, with details to be worked out between Mexico and the U.S. Department of Transportation’s Federal Motor Carrier Safety Administration should Congress approve the measure.

The Mexican vehicles would be required to meet U.S. safety and environmental regulations, and Mexican drivers would be required to demonstrate an ability to read English.

In exchange, President Calderon said Mexico would lift punitive tariffs against dozens of U.S. manufactured products, making it easier for U.S.-made goods to be sold in Mexico. Those tariffs are adding some $2 billion annually to the cost of U.S. goods imported into Mexico, according to U.S. officials.