Mexico City (AP) -  Juan Martinez has seen drivers doze off from fatigue while he's taking a bus from Houston to his hometown in San Luis Potosi, Mexico.

"This is very dangerous," Martinez said, waiting with suitcase in hand in front of Autobuses Lucano, one of the many smaller bus companies that offer service from the United States to Mexico.

But Martinez and the thousands of riders, mostly Mexican immigrants, looking for a cheap way to get home aren't deterred by recent crashes and the recent drug smuggling indictments involving several of these bus companies.

"There is just no other way for many of us to go home," he said just before boarding a bus bound for his hometown in north central Mexico.

One of the allures of these companies is their low fares. Martinez's one-way ticket cost $70. In comparison, a ticket on a well-known carrier like Greyhound from Houston to Montgomery, Ala., roughly the same distance as Martinez's trip to San Luis Potosi, costs $128.

Unlike Greyhound, which doesn't go south of the border, these smaller bus companies travel from U.S. cities to Mexico. The companies have small fleets — usually only a few buses — and their terminals are mostly located in Hispanic neighborhoods. While the ticket prices are low, the bus trips can be long. Many of the buses offer such amenities as movies onboard.

Attorneys for passengers injured in bus crashes, safety experts and court records say the industry, while convenient, has a long history of accidents in the United States and Mexico and repeated safety violations, including overworked and undertrained drivers.

But federal regulators and other officials say the companies' safety records are no worse than traditional carriers.

In the most recent crash, a bus traveling from Monterrey, Mexico, to Houston veered off a highway on Jan. 2 near Victoria.

One passenger was killed and another eventually lost an arm. The driver was cited for falling asleep and driving with the wrong kind of commercial license.

Weeks earlier, on Nov. 25, a bus owned by Dallas-based Tornado Bus Co. collided with a pickup truck and a tractor trailer near Forrest City, Ark. Three passengers and the truck's driver were killed.

Police say the driver, facing murder charges, was under the influence of amphetamines and didn't have a required relief driver with him.

Houston attorney Terry Bryant, who represents 12 of the passengers injured in January's crash, also represented passengers in a September 2002 accident in Mississippi caused when the driver and replacement driver tried to switch seats while the bus was going 70 mph.

"That's where efficiency outweighs safety. It's ridiculous," Bryant said. "It's the kind of prank you'd see in an awful TV show."

A federal jury in 2006 awarded one of the passengers injured in the crash $5 million. The judgment was overturned on appeal and the case is set for retrial.

A Houston judge in 2005 awarded a family $1.2 million after their van was hit by a bus owned by Houston-based Garcia Tours in an accident in Monterrey, Mexico, a year earlier, killing two. The judge found the driver negligent and faulted the company owner for her hiring, supervising and training practices.

But Steve Norris, a Houston attorney who represented family members, said they didn't see a penny because the bus company couldn't pay and its insurance policy did not cover accidents in Mexico.

However, the federal agency that regulates commercial truck and bus traffic says such accidents don't show an accurate picture of these types of companies, which are required to follow all safety regulations in both the United States and Mexico.

"Their overall safety performance is no worse or better than long standing traditional carriers," said Duane DeBruyne, a spokesman for the Federal Motor Carrier Safety Administration.

But Norris, who has represented passengers injured in several bus crashes, said many of these companies are "fly by night" operations that close up shop when they get in trouble. John Sloan, who represents the family of a Salvadoran man killed in a January 2006 van crash in Utah, said he had to put a newspaper ad giving notice of a lawsuit after repeated attempts to find the Houston-based company owner, including ones that led to vacant buildings, were unsuccessful. The owner, Jose Luis Macias, remains missing but the case is still going to trial in November against the insurance company.

Bryant said a bus may be owned by one company but then leased to another, making it difficult to determine who would bear responsibility for a crash.

In the bus crashes in Victoria and Mississippi, several companies were cited as either owning, leasing, or operating the vehicles.

"It's very much a tangled web," Bryant said.

Larry Warren, an attorney for Capricorn and International Charter Services, two of the bus companies connected to the bus in the Victoria crash, declined to comment about the case.

In addition to safety concerns, some bus companies are being accused of taking part in the smuggling of drugs and illegal immigrants.

Last week, authorities said five companies with offices in Mexico and Texas had smuggled cocaine and marijuana in their buses into the United States since 2001.

Another company, Houston-based Pegasso Tours, forfeited one of its buses after authorities in 2005 found 136 packages of cocaine behind the driver's seat after crossing the Mexico-Texas border. Drugs had been found three other times aboard buses owned by Pegasso, according to court records.

In February, six men were sentenced for their roles in an illegal immigrant smuggling operation that hid people in the offices of a Houston bus company, National Super Express Van Tours, and used its vehicles to transport them to stash houses.

But such bus companies are not indicative of the industry as a whole, said Steve Campbell, executive director of the Commercial Vehicle Safety Alliance.

"If they were representative of the entire industry, we would all be in trouble," said Campbell, whose group is made up of local and federal officials that enforce motor carrier safety laws in the United States, Canada and Mexico. "The statistics don't bear out there is a problem in that segment of the industry or in those kinds of operations."

Capt. Steven Sullivan, with the Texas Highway Patrol's commercial vehicle enforcement section, said roadside inspections by troopers of commercial buses result in less than 10 percent of drivers being taken out of service for problems associated with proper licensing or hours spent behind the wheel.

Around 22 percent of buses are taken out of service for problems with brakes, tires or other defects.

Sullivan said these out of service rates for Texas are similar to commercial vehicle inspections done nationwide.

"Of course in a perfect world, you want voluntary compliance," he said. "You would like it to be zero. But you also have to be realistic."

The bus that crashed through a guardrail Friday morning in Sherman, Texas, was owned by Iguala Busmex, Incorporated.

17 people died and at least eight more are in critical condition.

Sunday the National Transportation Safety Board revealed they had linked two companies, Iguala Busmex and Angel Tours to the unlicensed bus and that both had received past unsatisfactory reviews.

Meanwhile, the Federal Motor Safety Administration has ordered those companies linked to the bus involved in the fatal Texas crash to cease all commercial operations.

The bus was carrying 55 Vietnamese Catholics to Marian Days in Carthage.