The responsibilities of county authorities
County authorities are usually responsible for offering school transport to pupils in primary and secondary school in their county
They are responsible for all transport due to long school routes, disabilities, and temporary injuries or illnesses. County authorities are also responsible for supervision and travel attendants for pupils in upper secondary schools.
Municipalities are responsible for transport due to particularly hazardous or difficult school routes for pupils in primary and lower secondary school (who do not have a long school route). They are also responsible for travel attendants and supervision for primary and lower secondary school pupils. As mentioned above, county authorities are responsible for transport due to long school routes, and therefore in many cases municipalities and county authorities have to work together to ensure safe transport.
Read more here: https://www.udir.no/regelverkstolkninger/opplaring/Skoleskyss/udir-2-2019-retten-til-skyss1/7.-hvem-har-ansvaret-for-skyssen/7.1-nar-er-fylkeskommunen-ansvarlig/