Their car mileage can be expected to rise sharply when they take control of two to three primaries, sometimes widely scattered.
The council was yesterday asked to back a plan to cluster 135 schools with under 145 pupils in a strategy to sharpen management and release heads from teaching commitments. At present, the 135 schools have heads who teach.
Bruce Robertson, education director, said the success of 15 cluster pilots, which started in Raasay, Staffin and Carbost on Skye, has proved the model is effective. Three clusters have already been favourably received by inspectors.
Mr Robertson said the abolition of the 1956 Schools Code, which stipulated there should be one headteacher for every school, meant the way was now clear for a more appropriate management structure.
Class-committed heads found it particularly hard to provide leadership and direction across a complex range of areas and priorities while carrying on with their classroom duties. "It is questionable whether the traditional pattern of management of smaller primary schools remains entirely appropriate," he said.
The director told councillors of difficulties recruiting heads, especially for smaller schools, and of continuing declining rolls, despite inward migration. There are likely to be 2,000 fewer pupils within four years.
Highland is promising full local consultation on reviews, the appointment of principal teachers to clusters, and the creation of new posts of care and welfare officers. These will be ancillary staff who cover when heads have to divide time between schools.