A row has broken out about giving ALL teenagers free bus travel.
Some people say it shouldn't be allowed - because the kids might behave badly and put passengers and drivers at risk.
It comes after Labour MP David Chaytor called for a nationwide scheme for under 21s who are at school, college or training for work.
Under 18s in London already get some free transport - and experts say there has been more violence since the scheme came in.
Unite - an organisation which represents transport workers - said there were lots of problems.
A spokesman for the group said some staff had been "spat at, punched at and kicked".
Teaching organisations have suggested that free travel should come with special conditions.
One idea is that kids must get their parents' approval to get a pass and, if they misbehave, the pass will be taken away.
The MP who put forward the plan says it will encourage kids to use public transport and reduce traffic jams.