The Colorado State Patrol is investigating four crashes and two traffic stops that involve 70 suspected illegal immigrants.

Trooper Eric Wynn with the Colorado State Patrol said there were multiple passengers in each of the vehicles.

Three of the Tuesday morning crashes were near Brush, Colo., and one occurred in Siebert, Colo.

According to the CSP, at 6:35 a.m. a 1995 Ford Econoline with 16 people inside lost control and rolled on U.S. Highway 6 at the junction of Interstate 76 near Brush.

At 7:11 a.m. on Interstate 70, near Seibert, Colo., a Chevrolet Suburban with 10 occupants aboard rolled.

At 8:03 a.m. on I-76 near Brush, a 1999 Chevy Suburban rolled with four people inside.

A few minutes later -- in the same area -- a 1998 GMC van with 12 occupants rolled.

In all of the crashes, the occupants received only minor injuries or were not injured. Icy roads from Monday's wintere storm were to blame. Immigration and Customs Enforcement agents have taken everyone involved in custody.

Authorities are also investigating two other morning incidents on the Western Slope with more than 30 suspected illegal immigrants.

At 7:54 a.m. troopers stopped a 1995 Chevy Astro van for a traffic violation on eastbound I-70, near Glenwood Springs. Twenty suspected immigrants were inside the van. At 8:50 a.m. troopers pulled over a 1995 Chevy Astro van on eastbound I-70 near Wolcott, Colo. The vehicle had 11 suspected illegal immigrants.

All of the occupants inside the vehicles are Mexican nationals, the CSP said.

One Monday, 42 suspected illegal immigrants were taken into custody after two separate crashes on I-70 and Interstate 75.

One occurred when a van and a semi-trailer collided along I-76. The CSP said a Ford van was headed east on I-76 about 5 p.m. Monday, when the semi driver tried to merge with other eastbound traffic. The driver of the van lost control, spun around and hit the front of the truck before both vehicles went off the road. Authorities say 25 suspected immigrants fled the scene and ran to a McDonald's restaurant in Brush -- where they were captured.

Seventeen people were taken into custody after their Chevrolet Suburban crashed near Strasburg. Their vehicle flipped. One person was taken to the hospital with minor injuries.

The state patrol said there is an increase in human trafficking this time of year. Troopers estimate they encounter more than 500 undocumented immigrants on a weekly basis on Colorado highways.

So why the increase?

Claude D'Estree, a visiting professor at Denver University's Graduate School of International Studies, said, "If the need is high enough, yes, of course they will make an attempt to cross (the border) to find work. We want cheap labor, in fact, so cheap that we don't often want to pay for it."

State Sen. Peter Groff is sponsoring two bills that would make smuggling and trafficking a felony. Violators face five years in prison.