Reviewing Age and Condition of Bus Fleet

Making the Way for Environmentally Cleaner Buses

Districts should survey their fleet of buses to assess age and condition and determine which buses are ready (near term, especially) for replacement. Compiling assessment information in advance (e.g., bus age, manufacturer, engine models, usage and condition), allows the districts to plan for expenditures and also be prepared if funds become available through the Federal government, state agencies, local communities or public/private entities. Fleet information can be detailed on a "Fleet Information Table" (PDF, 1 page, 72K, About PDF)

Replacing Buses-- Things to Consider:

Which buses should be selected first for replacement? The most cost-effective model years to target for replacement, based on pollutant emissions like particulate matter, are pre-1990 school buses. EPA emissions standards for heavy-duty vehicles for particulate matter decreased by well over 50% in 1991, and were more than halved again in 1994. The resulting emission reductions based on EPA's regulations can help a school district target the appropriate bus engine model years to consider for replacement. EPA dynamometer emission tests as well as modeled results support the fact that school districts should consider targeting their buses with the oldest engine model years first for replacement. The following list suggests target engine model years in order of priority for replacement.

Pre – 1978
1979 – 1987
1988 – 1990
1991 – 1993
1994 – 1997
Post 1997 – Evaluate available safety factors as well as emission standards.

Targeting pre-1990 school buses for replacement is not only key in getting rid of the buses that pollute more, but is a cost-effective strategy since older buses often have increased maintenance concerns and may have decreasing fuel economy benefits. Therefore, it is more cost-effective to replace older, pre-1990 vehicles which certainly won’t last as long as newer buses in addition to having higher diesel emission rates and less stringent safety equipment.

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What if the buses built in 1990 or earlier are still being used by the school district for student transportation?

Are these buses being used on a daily basis for student transport?

If yes, consider using these very old buses on shorter routes, where students are not on the buses for a long time. Also, rank these buses as high priority for future replacement and ask the local school bus sales representatives to update you on the status of their buses’ ability to meet or exceed current US EPA new diesel engine emission standards as well as other current safety features, which include those that are listed on the School Transportation News web site.
- Also, make sure that the school district implements a reduced idling and operational practice policy so that drivers are aware of limiting the amount of emissions to which students are exposed. For more information, visit our Idling Reduction web site.
- Assure that all bus engines are well maintained.
If no, it is assumed that these buses are for special event trips or are emergency back-up buses. When in use, consider the amount of time that students are on these buses. Try to limit the amount of time that students spend on these buses until the district can afford to replace these buses with cleaner, newer buses.
- Also, make sure that these buses follow school policy on reduced idling. For more information, visit our Idling Reduction web site.
- Assure that all bus engines are well maintained.

Buses built in 1991 and later have additional options...

Consider retrofitting the buses that will be maintained in the fleet for several years with verified emission control technologies and/or use cleaner fuels.
Consider other districts in the community when looking to replace some of the post-1990 buses with newer buses. Work with nearby school districts that may be more economically challenged and encourage them to survey their fleet. If they have buses built prior to 1990 but cannot afford brand new buses, work with the community to provide your district's newer buses as a replacement alternative for your neighboring district. Overall, this is a win-win situation for air quality in the whole community.