Tara and Ann Marie have won acclaim for their idea
Tara Davies, 16, and Ann Marie Jones, 16, from Pontarddulais Comprehensive school near Swansea, came up with a bus pass, with its own code of conduct, which has dramatically reduced problems.
The girls' efforts have been recognised with a Diana, Princess of Wales Memorial Award and it has attracted interest from other schools.
The school, which nominated them, said they are a wonderful example to others.
Jan Waldron, deputy head, said: "Bullying was the main problem.
"I had two or three phone calls a week from parents, bus drivers and members of the public about the behaviour of some children.
Pupils became scared to travel on the school buses.
When things got too bad the girls decided to do something about the situation themselves.
They organised groups of pupils and came up with the bus ID scheme.
Rules were introduced of no bullying, no swearing, no smoking and no disturbing the driver.
These are posted on the buses and information sheets distributed.
If any pupil breaks these rules then a corner of the pass is clipped.
If all four corners are clipped, that pupil must find his or her own way to and from the school.
More than £1,200 in sponsorship was raised to pay for a digital camera and a laminating machine to produce the cards.
Tara and Ann Marie said: "Kids were being bullied and were too scared to say anything.
"We spoke to the drivers about it and the teachers have been great."
But since the scheme has been introduced, not one corner has been clipped.
Miss Waldron said the scheme has had a tremendous impact.
Success
"There has been a huge improvement in behaviour", she said.
"Now, I get a complaint about once every six weeks.
"The beauty of the scheme is that it is self-regulating and that it has come from the pupils themselves."
Tara and Ann Marie are leaving school next week but have taken steps to ensure the scheme will continue.
They said: "We are very proud of our achievements and it is a pity we are leaving.
"But we have been holding interviews to make sure that whoever takes over will be okay."