Death-Defying Border Dashes : Immigration: Thousands swarm illegally past Mexican checkpoint and race north in southbound lanes of busy freeway.

About 3:15 Monday afternoon, three dozen men, women and children enacted a terrifying ritual that has become a new twist in the dangerous game played at the U.S.-Mexican border: running headlong into oncoming traffic.

A few hundred feet south of the port of entry separating Tijuana from San Diego, the group crept northward along a center divider separating northbound and southbound lanes.

At the command of a coyote, or alien smuggler, they clambered over the divider fence and sprinted into southbound traffic--past Mexican customs officers manning their booths at the border station, past a lone Mexican immigration officer who tried to stop them.

Once in U.S. territory, the group kept running on the freeway for several hundred yards, a chaotic charge against waves of onrushing vehicles, before they veered to the center divider of Interstate 5.

Motorists headed into Mexico braked and honked. Tourists and Mexican residents crossing overhead on a freeway bridge watched grimly and shook their heads. A U.S. Border Patrol officer filmed the scene with a video camera.

“They feel safe on the freeway,” said Jesse, a streetwise 22-year-old from Guadalajara, who was interviewed on the divider on the Mexican side as he prepared to make the same dash. “The migra won’t chase them there. It’s not so easy anymore to cross in other places. . . . Of course, it’s scary. Especially if you have kids with you.”

In the past month, hundreds of people have been making the desperate run through the Mexican customs station each day, as more and more illegal immigrants realize it is an effective route.

There have been no major accidents so far, but both U.S. and Mexican authorities said Monday that they must combat the practice before it adds to the toll of illegal immigrants who have died in freeway accidents at the border and farther north at the San Onofre immigration checkpoint.

A new U.S. proposal will probably involve reducing the number of lanes going into Mexico, thereby slowing traffic and giving Border Patrol agents an area in which to operate at the freeway port of entry, immigration officials said. Agents currently do not pursue illegal immigrants on the freeway for fear of causing an accident.

“It’s an immigration problem,” INS spokesman Rudy Murillo said. “And it’s also a safety problem.”

Details of the proposal will be announced today. It follows statements made during a San Diego visit last week by INS Commissioner Gene McNary, who told a San Diego business group that he has discussed the issue with Mexican officials and favors blocking some of the six freeway lanes at the border, Murillo said.

For several years, illegal immigrants have used the freeway divider to hike north after crossing the border nearby. But even for those accustomed to this anarchic spectacle, increasing use of the new route is alarming and attributable to a new fence at the border and other intensified enforcement measures during the past year.

In addition, Mexican authorities have been reluctant to interfere with illegal immigration in the past. Border Patrol officials say they have seen little response to their requests for help from Mexican officials at the port of entry.

“It needs to be addressed from the south side of the border,” Border Patrol spokesman Steve Kean said. “Our hands are tied over here.”

But it was clear Monday that Mexican authorities are also concerned.

Although the uniformed Mexican immigration officer stationed near the divider appeared somewhat overwhelmed by the number of people running past him, a special border police unit known as Grupo Beta has begun operating around the port of entry and made several arrests over the weekend, according to Mexican officials and others.

This represents a major change in the role of the plainclothes Grupo Beta, which was created a year ago and has been praised for fighting crime and violence against those trying to enter the United States illegally.

In addition, Mexican officials are planning to replace a tattered fence separating northbound and southbound lanes with a stronger wall to make it harder for people to reach the Mexican customs lanes, according to Jorge Rojo Deschamps, customs administrator in Tijuana.

Deschamps said it is not the role of blue-uniformed Mexican customs officers to interfere with those who are trying to cross illegally, but that his officers are cooperating with both U.S. and Mexican immigration authorities.

If the lanes heading into Tijuana are reduced, it will mean increased waiting time for vehicles entering Mexico, he said

“We have to do whatever we can,” Rojo said. “We cannot have women and children running through these lanes. We don’t want an accident to happen.”

On a bridge in Mexican territory where coyotes and their wary charges watch the customs station and bide their time, Ramiro Cardenas said that, as a former illegal immigrant in the U.S., he understands what could motivate people to run a gauntlet between speeding cars.

“I would do it too,” he said. “If I needed the money, I would do it too.”