TIJUANA  A traffic nightmare unfolded Wednesday in the city's busiest areas when thousands of motorists were diverted from the closed San Ysidro border crossing to the one in Otay Mesa, snarling traffic along the way all day long.

By late afternoon, the wait to cross at Otay Mesa had stretched to more than four hours. 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.

Public officials on both sides of the border announced plans to ease traffic. The U.S. Customs and Border Protection said that when regular cargo inspections ended at 8 p.m. Wednesday, those lanes would be used for vehicle traffic until 5 a.m., when cargo inspections would resume. The port of entry at Tecate also would remain open all night.

And in Tijuana, Mayor Carlos Bustamante announced a plan that blocked access to the San Ysidro

crossing and eased traffic to the Otay Mesa one. He urged those who did not have to absolutely travel to the United States to stay away from that port of entry.

All that was too late for Alejandro Escobar.

The San Diego resident arrived at the San Ysidro border crossing around 9:45 a.m. to return home. A construction canopy collapsed there about an hour later and he found himself being sent away from the area.

"The problem was that there was no coordination whatsoever," said Escobar. "No transit police, nothing. Who knew where you should go? That was wrong."

He made his way to the Otay Mesa border crossing, where at mid-afternoon he was still waiting to cross into the United States  more than six hours after he had arrived at San Ysidro.

The director of Tijuana's transit police, Adrián Hernández, said that four main avenues in the Río zone leading to the San Ysidro crossing had been blocked -- calle Segunda, Paseo de los Héroes, Centenario and Padre Kino. He said traffic was being sent to Otay Mesa, some five miles away.

Instead of traveling through the Río zone, which had been jammed since the collapse at the border, he urged residents to take alternate routes, to reach that area.

And starting at 7 p.m., three temporary lanes were to be open on 12th Street (calle 12), in the Centenario district, which leads to the gates at the Otay Mesa border crossing, according to Angélica Echegoyén, deputy director of Mexican Customs in Tijuana.

Traffic in the Río Zone was already going to be a challenge Wednesday before the collapse at San Ysidro. A main thoroughfare had being partially closed ahead of Independence Day festivities Thursday.

Moments after U.S. authorities closed the port of entry 10:45 a.m. following the collapse, the thousands of motorists waiting to cross flowed back into the Río zone, causing a gridlock on avenida Paseo de los Héroes, between the Cuauhtémoc and Independencia monuments, and slowing traffic to a crawl on the adjacent Vía Rápida Poniente, near the Tijuana Cultural Center.

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 how and when they would be able to arrive to their destination.

Omar.millan@sandiegored.com