Expansion work closes busiest US-Mexico border crossing

Heavy machinery and construction crews work on the first day of a 57-hour closure of all Mexico-bound car traffic at the San Ysidro border crossing, where about 50,000 cars and 20,000 pedestrians go back and forth every day in San Diego, Calif., on Saturday, Sept. 23, 2017. Once complete in 2019, there will be 10 southbound lanes, twice the current number, and eight more lanes from Mexico to the United States. (AP Photo/Elliot Spagat)
Heavy machinery and construction crews work on the first day of a 57-hour closure of all Mexico-bound car traffic at the San Ysidro border crossing, where about 50,000 cars and 20,000 pedestrians go back and forth every day in San Diego, Calif., on Saturday, Sept. 23, 2017. Once complete in 2019, there will be 10 southbound lanes, twice the current number, and eight more lanes from Mexico to the United States. (AP Photo/Elliot Spagat)

SAN DIEGO (AP) - Detoured traffic into Mexico from the busiest border crossing with the United States was unusually light Saturday as motorists heeded calls to avoid freeways during a weekend shutdown for southbound cars.

There were no significant delays on the first day of a 57-hour closure of all Mexico-bound car traffic at the San Ysidro border crossing, where about 50,000 cars and 20,000 pedestrians go back and forth on weekdays.

Motorists who were directed east to the much-smaller Otay Mesa crossing posted photos to social media celebrating near-empty lanes through late morning.

"People aren't coming across," Anthony Kleppe, senior asset manager at the U.S. General Services Administration, said over the noise of backhoes moving concrete debris on California's Interstate 5. "They're choosing to stay home."

Northbound lanes remained open at San Ysidro, but cars were only about 10 deep, resulting in delays of only a few minutes. Motorists are accustomed to waiting more than an hour. The crossing was also open to pedestrian traffic, which was normal.

Crews were 40 minutes ahead of schedule by late morning, Kleppe said. They had removed a large metal canopy spanning southbound lanes into Mexico and were tearing up its concrete foundation.

U.S. officials repeatedly warned travelers to avoid driving to Tijuana from San Diego until the crossing reopens Monday at noon.