The Fairfax County School Board voted last night to stop ordering seat belts on new school buses in light of a federal study showing they do not reduce the risk of death or injury in an accident.

The county runs the nation's largest school bus fleet -- 1,100 vehicles, of which 263 have seat belts. The school system began ordering belted buses last year under pressure from parent lobby groups.

Last night's 9-to-0 vote, with board member Kohann Whitney absent, empowered Superintendent Robert R. Spillane to seek permission of the Board of Supervisors, which pays for new buses, to drop seat belts. It reflected the findings of a National Transportation Safety Board study released in March that concluded lap belts do not improve safety and in some cases may detract from it.

The federal study said that buses built after 1978, when new safety standards took effect, are "an extremely safe form of transportation" even without belts. Those standards required padded seat backs, higher seat backs, and seats spaced more closely together for a compartmentalized effect.

The Fairfax vote means that 186 buses on order for the fall will not have seat belts, assuming the supervisors agree with the School Board. The action would leave Montgomery County as the only area jurisdiction continuing to buy buses with seat belts. The change will affect only full-size buses; smaller buses for handicapped students will continue to have belts. Seat belt use is optional on full-size buses that already have them.

In other business, the School Board appointed Johnie Forte Jr., an Army brigadier general, as assistant superintendent of general services, with a $65,000 salary.