Border Patrol agents are seeing a spike in the number of people hiding in vehicles trying to sneak through highway checkpoints.
"It's something that we see that's very dangerous," said Yesenia Lopez, a U.S. Border Patrol Agent in the El Paso area.
People are crammed into hidden compartments, stashed in trunks, or loaded like cargo into 18 wheelers by smugglers trying to get past highway checkpoints.
There has been an uptick in these incidents in recent weeks at checkpoints in the Rio Grande Valley. In one 24-hour period in April, Border Patrol Agents rescued 49 people hidden in different compartments in vehicles.
"Falfurrias Station agents arrested a man, who is a United States citizen, attempting to smuggle 38 undocumented aliens locked inside a tractor trailer," according to the Border Patrol Rio Grande Valley Sector news release about the incident.
Specially trained "super dogs," who can detect attempts to smuggle both drugs and humans, help agents at checkpoints and border crossings. The dogs distinguish between a person who is riding in a car and someone who is hiding.
"That particular scent is okay in certain parts of the vehicle. If somebody is in the trunk it will alert," said Ruben Jauregui, a Customs and Border Protection officer in El Paso.
Just on the stretch of Texas border in El Paso county, 30,000 vehicles a day enter the United States. Smuggling organizations all along the border try to use heavy traffic to slip people into the country undetected.
"They'll smuggle someone who doesn't have an entry document into the U.S. or maybe somebody who may be wanted," said Jauregui.
Over the years smugglers have tried a variety of creative methods to conceal people in vehicles from door panels, to engines, to a man sewn into a car seat who was trying to cross the California border.
Border Patrol Agents at a checkpoint in the Rio Grande Valley recently discovered two men crammed inside a car speaker box.
Some people have died in trunks, others in cargo trucks including 18 immigrants who suffocated in stifling heat after they were locked inside the tractor trailer in Victoria, Texas in 2003.
The recent uptick in smuggling attempts using vehicles has led to concerns as temperatures rises so will the danger.
"Sometimes there's not enough oxygen in the area or just with the heat someone could die," said Lopez.