Colorado school districts are facing rising costs to keep buses on the road as diesel prices climb and funding to help them switch to cleaner vehicles has dried up or been paused. Jefferson County Public Schools operates about 393 buses, which travel more than 20,000 miles each day. Nearly all run on diesel, and the district’s fuel spending was about $100,000 higher in the first quarter of this school year than in the same period last year, transportation director Nathan Reimer said. Diesel topped $6 a gallon in Colorado last month, roughly twice its price only a few months earlier. Reimer said the increase has led the district to consider whether routes could be made more efficient if prices remain high. He said he had not budgeted for the effect of the war in Iran on fuel costs. School systems have limited options for absorbing higher expenses, said Peter Manella, public policy liaison for the National Association for Pupil Transportation. Unlike businesses, districts cannot simply pass fuel costs on to customers. If pressure continues, districts could face choices involving transportation to athletic events or field trips, he said. No such cuts were reported as having been made in Jefferson County. Boulder Valley School District is less exposed to diesel prices because it began diversifying its fleet in 2017. Most of its buses run on unleaded fuel or propane, with several electric buses in service. Its diesel spending is down 12% this year, assistant transportation director David Self said. Bus driver Jill Sellars has driven an electric school bus, which she named Evie, since 2020. The bus is quiet and powerful, she said. Boulder Valley began changing its fleet as part of efforts to reduce local carbon emissions; the lower exposure to diesel costs has become an additional benefit. For most districts, however, switching fuels is not a quick fix. Electric buses cost more than diesel models and require charging infrastructure, while propane buses and other alternatives also require investment and planning. Federal and state programs helped Colorado districts cover some of those costs. The 2021 federal infrastructure law set aside $5 billion for cleaner school buses nationwide. At least $21 million went to Colorado, helping schools and districts acquire 78 electric or other cleaner-burning buses. The Trump administration halted the federal program earlier this year while it reviews and revamps it. Colorado allocated $65 million in 2022 to help districts transition to cleaner-burning fuels, but that funding has been spent. Without new assistance, districts facing immediate fuel bills may have fewer resources to make the longer-term shift to cleaner fleets.