Calls to give teenagers free bus travel have been roundly criticised amid fears of anti-social behaviour.
Labour MP David Chaytor is calling for a nationwide scheme to benefit people under the age of 21 who are in education and training.
But critics have cited London, where a scheme for teenagers up to 18 has seen a rise in violence and graffiti.
The head teachers' association said the passes should only be issued after a written guarantee of good behaviour.
Clarissa Williams, vice president of the National Association of Head Teachers, said that although most young people would behave and use the passes responsibly, there would be some who misused them.
"I would suggest that they would have to apply for the passes with a written parental guarantee that should their child not behave on the bus, then that pass will be withdrawn."
But the MP for Bury North, David Chaytor, said there were clear benefits for free or subsidised travel on buses.
"It makes obvious sense in terms of encouraging young people to use the bus and the train more, to reduce congestion on our roads and of course to help with the problem of climate change by reducing pollution and carbon dioxide emissions."
A Transport for London spokesman said its buses were a "safe and reliable" way to travel.
"Crime is committed by only a small minority, and we are working extremely hard to tackle this element," he said.
"This approach is working. The latest figures show that bus crime involving suspects under 16 has gone down by 19% in the first six months of this year."