Headteachers have given a cautious welcome to new powers to discipline pupils who misbehave while travelling to or from school or college.
The first All Wales Travel Behaviour Code, published this week, aims to promote good behaviour and improve pupil safety.
The code will come into force at the start of the spring term in January and will cover all forms of transport, including bus, train, walking and cycling for all learners aged five to 19.
It will give schools and local authorities the power to take action against pupils who misbehave while travelling to school.
For the first time in Wales heads will be able to impose sanctions for incidents that occur beyond the school gate.
The new powers have been generally welcomed by the profession, but some heads have expressed concern about their new responsibilities.
John Hopkins, head of Gwernyfed High School in Powys, said he had previously taken action against pupils whose behaviour while off premises had brought the school into disrepute.
But he said: "I don't particularly want to end up with absolute responsibility for everything that happens outside the school gates. To a large extent it should be the responsibility of parents to make sure their children behave when they are not in school."
Neil Foden, head of Ysgol Friars in Bangor, said: "I have mixed feelings; it's a question of jurisdiction and responsibility.
"This makes it clear that schools can take action in situations where parents don't fully shoulder their responsibilities.
"But we don't want to be held responsible for every incident that happens on school transport."
Anna Brychan, director of heads' union NAHT Cymru, said: "A lot of the bad behaviour caused on school buses arrives at the school gates in any event. Many schools find themselves dealing with these incidents on a regular basis.
"There will be some concern about the way this works in practice and what schools are responsible for. But we are hoping that fears will be allayed when guidance is produced."
The guidance, due to be published in December, will require closer working between schools, pupils, parents, transport operators and local authorities to ensure that any incident relating to learner travel is dealt with in the most appropriate manner.
An Assembly government spokesman said: "We anticipate that schools would have a nominated person to deal with travel behaviour and this will be reflected in the guidance, but the application of this is a matter for schools to decide themselves. We do not believe that this will place a significant additional burden on teachers."
The code comes seven years after 12-year-old Stuart Cunningham Jones was killed when his school bus crashed in mid Glamorgan.
An inquest jury returned a verdict of accidental death, having heard evidence of misbehaviour on the bus moments before the crash.
The code will now encourage pupils to "Tell a teacher, parent or driver" about any bad behaviour they see when travelling from home to school.
Operators and drivers will have a responsibility to report any incidents of poor, disruptive or unsafe behaviour to local authorities and schools.