CLEVELAND —  David Murphy says while other kids were "freaking out," screaming and hollering while their runaway school bus headed toward an oncoming semi, he decided to go up front to protect his classmates.

"I took the wheel and had to turn the wheel on the sidewalk," the 11-year-old explained Wednesday on ABC's "Good Morning America," in his first public comments since he steered the bus into a bridge pillar and out of danger on Monday.

His mother said she was amazed.

"When I saw the precision of the bus, it seemed like it was parked," Patricia Murphy told the program. "I couldn't believe it and that he had that strength and that direction."

She said she figured out a reason her son was so quiet afterward was that he was terrified he'd get in trouble for taking the wheel.

David was among 27 students headed to a charter school on Monday when the driver stopped at a service station, pumped about $40 of fuel and went into the rest room while the bus was parked and running.

In his absence, the bus began rolling about 300 feet down a side street that swoops through an industrial area and was on a collision course with a semitrailer.

David told police he first tried to pull the emergency brake. When that didn't work, he grabbed the wheel and stopped the bus by guiding it into a bridge's concrete support pillar.

"He veered the bus into the last possible pillar," said Cleveland Fire Department spokesman Larry Gray. "He was a shy kid. I don't think he grasped the magnitude of what he did."

It's not clear why the bus started to roll, police Lt. Thomas Stacho said. Investigators did not find any mechanical problems and a gas station employee watching the bus said none of the children appeared to tamper with anything, he said.

Many of the students screamed, and some jumped out as the bus rolled. Fifteen were checked later at hospitals, but severe injuries were avoided.

"We are excited that every one of those kids went home, and we spoke with all of their families today," Head of School Alexis Rainbow said Tuesday.

A teen who tried to protect younger children on a the bus said Tuesday that the students aren't angry with the driver.

Michelle Howard, 15, told Cleveland television station WOIO that she ran toward the front of the bus when it began rolling and saw that it was on a collision course with the semitrailer.

"None of the kids are mad or angry with him," Howard said about driver. "It was more disappointed — disappointed that he wasn't there to protect them."

The driver, Michael Weir, 57, will be cited for leaving a vehicle unattended with the keys in the ignition and for registration violations, Stacho said Tuesday.

Weir has a valid commercial driver's license but wasn't registered with the state as required, police said. His license was suspended for six months in 2006 and was reissued July 16.

Aqua Limo, identified by the fire department as the company owning the bus, issued a statement Tuesday that it does not own the bus involved in the crash, that the school informed Aqua Limo on Friday that its services were no longer needed and that the school hired Weir.

But Rainbow said in a brief news conference outside of the school that Weir was Aqua Limo's employee. She said Weir was on his fourth day Monday driving a school route for Aqua Limo, and the school didn't tell Aqua Limo its services were no longer needed until Monday night, after the mishap.

Highway Patrol Sgt. Craig Cvetan said the state inspected a bus believed to be the one involved in the crash as recently as last August, and no safety violations were noted. Some violations were found in previous inspections, such as a defective exhaust and battery holder.

But Cvetan said he could not say for certain that the bus involved in the accident was the same 1989 vehicle inspected. The patrol was trying to match vehicle identification numbers.