TIJUANA – A traffic nightmare unfolded Wednesday in one of the city’s busiest areas when thousands of motorists were diverted from the San Ysidro border crossing and sent to a main thoroughfare that was being partially closed ahead of Independence Day festivities Thursday.

U.S. authorities closed the port of entry after a construction canopy collapsed around 10:45 a.m. atop of vehicles waiting to cross the border, injuring at least three people.

Authorities evacuated all the lanes and sent the traffic back into the Río zone, the city’s main business and tourist zone.

The thousands of cars caused a gridlock on avenida Paseo de los Héroes, between the Cuauhtémoc and Independencia monuments, and slowed traffic to a crawl on the adjacent Vía Rápida Poniente, near the Tijuana Cultural Center.

The motorists who had been at San Ysidro were directed to the Otay Mesa port of entry. By 3 p.m., traffic in the regular lanes was backed up to a nearby bridge, more or less normal for that time of day. But traffic waiting to use the Ready Lane had backed up about eight miles, and those waiting to use the SENTRI lanes had stacked up even farther.

To accommodate Mexican Independence Day festivities, the municipal government had announced that it would close starting at 10 a.m. Wednesday the west-to-east stretch of avenida Paseo de los Héroes, between calle Manuel Márquez de León and Independencia monument traffic circle.

Starting at 10 p.m., city officials planned to shut down all vehicle traffic on avenida Independencia, from Sánchez Taboada Boulevard to the Independencia traffic circle, in front of the Centro Cultural Tijuana.

The streets are to remain closed until Saturday at 5 a.m., when the festivities are to end.

Before and during the festivities, however, vehicle traffic will be allowed on a stretch of Paseo de los Héroes, between the Cuauhtémoc and Independencia monuments.

But many motorists in Tijuana were not thinking about the holiday; all they wondered when they would be able to arrive in their destination.

Omar.millan@sandiegored.com