More than a dozen people were taken to Atlanta hospitals Friday after their airport shuttle rear-ended an 18-wheeler.

The operator of the hotel shuttle, The Atlanta Journal-Constitution has learned, has had a number of violations recorded in the past two years.

The tractor-trailer was making a legal U-turn on Loop Road just south of the Virginia Avenue exit from I-85 when the shuttle bus collided with the trailer, College Park Police Sgt. Keith Stanley said.

“The shuttle was not able to stop,” Stanley said.

College Park-based MTI Limo & Shuttle Services Inc., the operator of the shuttle, has had several violations reported to the Federal Motor Carrier Safety Administration.

The company, started in 1990, operates limousines and shuttles with a fleet of luxury sedans, stretch limousines, vans, Lincoln Navigators, mini-buses, limo-buses and luxury motor coaches, according to its website.

In Friday’s accident, police said none of the 15 passengers on the bus were wearing seat belts, even though the shuttle was equipped with them.

“With that kind of vehicle, anything in the rear could be thrown to the front of the bus,” Stanley said. “If there were seat belts available in the bus, the passengers should have been wearing them.”

There is no federal passenger seat belt requirement in passenger vehicles; only the driver is required to wear a seat belt, according to the Georgia Department of Public Safety.

Federal Motor Carrier Safety Administration records for MTI Limo & Shuttle show that of 13 relevant inspections, 11 resulted in vehicle maintenance violations in 2011, ranging from bus emergency exits that were defective or lacking to problems with emergency exit markings.

During one 2011 inspection, a driver was found without a medical certificate, leading to that driver being put out of service.

Also reported in the federal data was a May 2011 crash of a bus operated by MTI Limo in Sandy Springs, resulting in three injuries. The online report does not indicate who was at fault.

Six people from Friday’s accident, including one child and the driver of the shuttle bus, were taken to Atlanta Medical Center, hospital officials said. All but two adults were released.

“The driver had to be extricated from the vehicle,” Stanley said. “She suffered multiple fractures.”

Ten people, including a 12-year-old boy, were taken to Grady Memorial Hospital.

The 12-year-old was being held for observations, hospital spokeswoman Denise Simpson said.

As for the others, by Friday evening four had been treated and released, three had been admitted to Grady, and two were being evaluated and receiving care, hospital officials said.

The truck driver was uninjured, police said.

It is unclear how fast the shuttle bus was traveling on the 45-mph Loop Road at the time of the wreck, but Stanley said the bus skidded 158 feet before hitting the left side of the trailer.

“The vehicle was going at a good rate of speed,” Stanley said.

MTI Limo & Shuttle owner Mike Toye said he has no comment, pending the outcome of the investigation of the accident.

According to Hartsfield-Jackson International Airport, all shuttles operating at the airport except for the airport’s own park-ride shuttles are managed by independent operators. The airport said in order to get permits to operate the airport, the operators must have proper credentials from the Georgia Department of Public Safety or Department of Transportation, depending on the type of shuttle.

The Hilton Garden Inn Atlanta Airport North and the Hampton Inn & Suites Atlanta Airport North I-85 said the hotels contract with MTI Limo & Shuttle for airport transportation, and the shuttle service remains operating as the hotels’ owners are awaiting results of the accident investigation. The shuttle also serves the Fairfield Inn & Suites Atlanta Airport North.

The wreck was reported at about 10 a.m., police said. It shut down the ramp from I-85 northbound to Loop Road for several hours, but the road and ramp reopened shortly before 1 p.m.

Police continue to investigate the accident.