People walking into Tijuana, Mexico, from San Ysidro, California, will now be split into two groups at the border crossing by Mexican officials.
Mexicans will be allowed to walk through without being checked, but foreigners, including U.S. citizens, will be forced to present their passport, complete some paperwork and pay about $20 for a six-month permit, if they are going to stay for longer than a week.
"This is about putting our house in order," Rodulfo Figueroa, a Mexican immigration official in Baja, California, told the Associated Press.
"If the line becomes clogged up, we will just let everybody through," Figueroa added. "If we can't check everybody, we won't."
Figueroa believes that Mexico can handle about 1,000 foreigners per day with the new system, which went into effect today.
There were about 20 people who were not allowed to enter Mexico today because they didn't have their passports.
The San Diego Tribune notes that Mexico plans to build similar crossings to upgrade their border infrastructure.
On the other side of the border, a report by The Pew Charitable Trusts notes that 10 states and Washington D.C. currently issue driver's licenses, or equivalent certifications, to undocumented immigrants.
The states include: California, Colorado, Connecticut, Illinois, Maryland, Nevada, New Mexico, Utah, Vermont and Washington.