Alone, afraid, at risk
A: You're right to be anxious. Any school trip, even an outing as small as this, must be conducted within the framework of the local education authority's and the school's guidelines, and they will certainly specify that:
* there must be at least one accompanying adult for every 15 or 20 pupils.
Common sense suggests that there should be two. Who looks after the main body of pupils in an emergency if you're on your own?
* any accompanying adult who is not a teacher must have Criminal Records Bureau clearance
* a risk assessment has been carried out and approved by the person responsible for your school's visit - you've identified the hazard of the A road
* pupils should have agreed to a safety code, which relates to the specifics identified in the risk assessment, and parents should have given their consent
* there should be a register of pupils attending.
That sounds a big fuss for a little walk, but if you're acting outside guidelines then you are vulnerable if anything goes wrong. You're a newly qualified teacher. You should not be asked to take sole responsibility.
Look at the advice from the DfES, at www.teachernet.gov.ukvisits