This year, 1.6 million more kids are heading back to school riding in the newest advanced technology diesel buses, outfitted with the latest safety equipment alongside the cleanest, most fuel-efficient engine technology.
Since the end of 2017, school districts around the country have invested in more than 32,000 new advanced technology diesel-powered school buses, a jump of 6.5 percent over the previous period. According to Vehicles in Operation data supplied by IHS Markit, 94 percent of all school buses in operation in America run on diesel fuel. Almost half of these (46 percent) are equipped with the cleanest, near-zero emission diesel engine technology.
“As the numbers reveal, school bus transportation managers continue show confidence in diesel for pupil transportation needs, even with a growing field of alternative fuels,” said Allen Schaeffer, executive director of the Diesel Technology Forum. “Near zero emissions diesel power offers the best all-around choice for safe, reliable and affordable school transportation. Diesel remains the gold standard for pupil transport, due to its unmatched combination of features including fuel safety, energy efficiency, reliability, durability, established fueling and maintenance network, range and operational flexibility, secondary markets and low acquisition and operating costs.”
In total, more than 11.5 million kids ride in the newest diesel buses every day, traveling an average of 16,170 miles a year. The new generation advanced technology diesel buses, on the road since 2010, are equipped with the most advanced emissions control technology available: diesel particulate filters and selective catalytic reduction systems. These technologies capture nearly all fine particle (PM) and virtually eliminate smog-forming nitrogen oxide (NOx) emissions to near-zero levels.
School buses as a vehicle category are a small percentage of the overall emissions inventory. In California, for example, the most recent data from CARB reveals that school buses (gasoline and diesel combined) account for just 0.7 percent of all NOx emissions and 0.2 percent of organic gases from mobile sources.
While the National Association of State Directors of Pupil Transportation Specialists recommends that larger school buses stay in service no longer than 12 or 15 years, School Bus Fleet reports the average age of the U.S. school bus fleet hovers around 9.3 years. Just based on age, about 37 percent of school buses in use today have exceeded their service life or are approaching their retirement.
“School bus vehicle and engine manufacturers today are providing a range of advanced vehicle safety and fuel technology choices to serve their customers. Diesel continues to be the most chosen option,” said Schaeffer. “The lower-cost diesel powertrain option means more transport dollars are available for school districts to invest in more new buses outfitted with the latest advances in bus safety, communications, monitoring, seat-belts and routing technologies that improve overall transportation safety and comfort for riders.”
Many school districts have found they can lower their carbon footprint and overall emissions by switching from 100 percent petroleum diesel to blends of advanced renewable low-carbon biodiesel fuels, further reducing the emissions for all children who ride the bus as well as their home communities.
“Alternatives to diesel like gaseous fuels or electricity often depend on substantial and limited government or other special pricing or incentives, and come with higher acquisition costs that requires the build-out of new fueling or charging infrastructure,” said Schaeffer. “Limitations in performance of some alternative fuels may require more buses to cover the same routes or compromise safe pupil transport in extreme weather conditions. Due to their novelty, non-diesel fuel bus investments must factor in a limited secondary sales market. These and other considerations often drain funds that would otherwise be used in the classroom or to simply turn over the fleet to newer technology. A net result of deferred replacement cycles means more kids will be riding on older buses for longer, which is an outcome no one wants.”