Natasha Paton, from Cleghorn, near Lanark, was killed after a coach carrying 39 pupils and five members of staff from Lanark Grammar School crashed during a snowstorm.
The bus, which was going to Alton Towers theme park, smashed through Castledyke Bridge, Wiston, South Lanarkshire, and went into a river.
Traffic Commissioner for Scotland Joan Aitken, found "no evidence pointing to failings by the operator" of the coach.
Miss Aitken called Carluke-based James Purdie and Kenneth Purdie, who trade as Photoflash Services, to the public inquiry after an investigation by the Vehicle and Operator Services Agency.
Last year, a fatal accident inquiry found Natasha's death could have been prevented if she had worn a seatbelt and the driver had gone slower.
Sheriff Nikola Stewart, who oversaw the inquiry into Natasha's death on March 31 2010, released her findings in May. She heard that coach driver Raymond Munro lost control of the vehicle.
After the coach collided with the bridge, Natasha was thrown from the vehicle and drowned in the Garf Water.
Sheriff Stewart identified "reasonable precautions" that may have prevented Natasha's death.
She said Natasha may have lived if the driver "had travelled at a lower speed on the approach to and turn on to Castledyke Bridge and refrained from applying the brakes whilst negotiating that turn".
The sheriff said Mr Munro could also have refrained "from attempting to negotiate the turn on to the bridge at a speed of 23mph or more".
All 49 passenger seats were fitted with lap seat belts and teachers had checked pupils were wearing them before the coach set off. At least nine pupils, including Natasha, were not wearing seat belts at the time of impact.
During the inquiry, Miss Aitken was told that the necessary systems were in place and satisfactory but with some minor shortcomings.
The Driver and Vehicle Standards Agency evidence did not point to fault on the part of the operator in the lead up to the crash.
Miss Aitken issued a warning about improvements required by the business, but said that these would not have prevented the crash.