No - almost all large franchise school services use buses which go into regular service later in the day, or even on the same duty. Also, if a bus breaks down an hour away from the depot, with 60 school children onboard, is that better than having a bus break down on a frequent every 10 minute corridor, which buses dead-run many times a day to anyway, and passengers simply have an extra few minutes added onto their journey. School buses also go on motorways much more frequently, both in and out of service, and on roads quite a few drivers are much less familiar on.