Recent events like the San Bernardino shooting have focused attention on visa violations and border security.
But before politicians began calling for greater vigilance, plans were already underway to step up screening at one crossing.
Border agents in San Diego are now testing biometrics to screen who's crossing the border.
Civil liberties advocates say they're also testing the limits of privacy.
At the Otay Mesa border crossing, people are lining up to enter the U.S. Many are frequent crossers heading to work, to visit family, to go shopping.
Today, some of them are about to find out crossing the border now involves another step.
A row of brand-new kiosks greet them at the front of the line. Border agents help them feed their travel documents into the kiosks. Then, if they're a U.S. citizen, they're ushered across the border.
But the non-U.S. citizens are asked to stay back for a moment.
They have to stand still while a camera inside the kiosk scans their face and eyes.
"This is a national security issue, as far as looking for individuals who are violating the law." Customs and Border Protection assistant port director Joseph Misenhelter explains this is all part of a pilot program evaluating biometrics at the border.
The agency wants to know if tracking uniquely identifying facial features can help better screen people crossing the border.
For the next six months, Otay Mesa will be their testing grounds.
It's currently the only land crossing where pedestrians will have their faces routinely scanned.
If the test is deemed successful, face scanning could expand to other border stops.
"This will address certain issues as far as, is that the same person on the document, potential visa overstays. So we'll know with certainty, did that person really leave the United States?"
Most border crossers said they were fine with the new level of screening. Abel Gongora said he just hopes it cuts down on wait times.
"If that's going to improve that, you know what I mean?"
Gongora is an American citizen who lives in Tijuana for its cheap rent. But he works in the U.S. as a music instructor. The border can make his commute excruciatingly long.
"I really need to get over there. I need to get over there."
Even Mexican citizens said they were more concerned about wait times than anything else.
Cesar Quezara said getting his face scanned was no big deal.
"It's very easy. Now it's more quick. I think it maybe was two or three seconds."
But civil liberties advocates wonder if border crossers are too willing to trade their personal information for shorter waits.
Mitra Ebadolahi, a border litigation attorney with the ACLU's chapter in San Diego, is worried that focusing on physical features could contribute to racial profiling.
She tells border crossers they should be more concerned about the future of face scanning at the border.
"I would say your interest in getting through the border as quickly as possible is a valid one. But if you pay for that convenience by giving up a photo of yourself, and that photo then gets into a database - not just at the border, but potentially used elsewhere - and then is used to connect you to a crime you didn't commit, because you sort of look like a guy who the victim of that crime has identified as being the perpetrator, how would you feel about the government having that information on you indefinitely?"
Customs and Border Protection says these new biometrics compare favorably with the accuracy of fingerprint scanning.
And it says the images collected during this test will not be shared with other agencies.
As for whether or not the new screening improves wait times, border crossers may need to be patient to hear the results.
-- David Wagner, KPBS News