155.2800 is a Special Emergency [PS] allocation by the FCC.
Altho in recent years there has been the push be to more Emergency Medical [PM] there are still many PS licenses, which include School Bus Operations and dozens of other exceptions [Beach patrols, Vet's etc etc]
(viii) Persons or organizations oper-
ating school buses on a regular basis
over regular routes for the trans-
mission of messages pertaining to ei-
ther the efficient operation of the
school bus service or the safety or gen-
eral welfare of the students they are
engaged in transporting. Each school
bus operator may be authorized to op-
erate one base station and a number of
mobile units not in excess of the total
of the number of buses and mainte-
nance vehicles regularly engaged in the
school bus operation. Additional base
stations or mobile units will be author-
ized only in exceptional circumstances
when the applicant can show a specific
need.
Medical frequency used in NH [and possibly Maine] You could be hearing a base unit calling a maintenance person on it [they do that sometimes]