California’s Lower-Emission School Bus Program (LESBP) is a grant program that provides funds to purchase new buses to replace old, high-emitting public school buses, and to equip in-use diesel school buses with retrofit devices that significantly reduce toxic particulate matter emissions.

The primary goal of the Lower-Emission School Bus Program is to reduce schoolchildren’s exposure to both cancer-causing and smog-forming pollution. The program does not impose any regulatory requirements on school districts and their participation in the program is voluntary.

Currently, the LESBP allows for replacement of 1993 and older model year buses. The California Air Resources Board (CARB) has now determined that AB 923 funds—a source of school bus purchasing funds—can be used to replace school buses with a model year that is a minimum of 20 years old.

The majority of 1993 and older model year school buses in California have been replaced. CARB says that California school bus data, compiled from multiple sources, indicates that out of approximately 25,000 school buses in California, approximately 2,000 school buses are registered as 1993 and older model year school buses—about 8% of the State school bus population.

Multiple air districts have requested that CARB adjust the eligible school bus model year under the LESBP because those air districts no longer have eligible 1993 and older model year buses in their districts to replace. In order to enable air districts to continue to turn over the older school buses operating in California and allow flexibility in which buses are replaced, CARB has expanded school bus eligibility as follows:

• Increase model year eligibility to include buses that are a minimum of 20 years old or older;

• Allow buses with a model year that is 20 years old or older that have been repowered with newer engines to be replaced; and

• Give air districts discretion in determining the order in which buses are replaced. The oldest buses do not need to be funded for replacement first but districts are encouraged to replace school buses that have the greatest air quality impact.