The oldest school buses in the nation, which pose the biggest health risks to students and staff, are concentrated in the poorest districts and those with the highest proportions of students of color, a new data analysis shows. But the push for electric school buses appears to be slowly turning that tide.
Roughly 9 in 10 school buses run on diesel fuel. The average school bus is 9 years old. The older the bus, the more pollution it emits, research shows.
But an estimated 110,000 of the nearly half-million school buses on America’s roads were built before 2010. At least 6,300 were built before 2000.
Of the buses built before 2000, 36 percent shuttle children to and from school in the lowest-income districts, while only 17 percent serve the highest-income districts, according to a report published Monday by the nonprofit World Resources Institute’s Electric School Bus Initiative.
Just less than half of buses older than 24 years old are in districts with the largest shares of students of color, the report says. By contrast, districts with the smallest shares of students of color have only 8 percent of the nation’s buses built before 2000.
These numbers add to the growing concern over diesel school buses’ contribution to poor air quality, which affects students’ health and their academic performance.
While diesel school buses contribute a relatively small percentage of toxins in the air in any given place, they add yet another toxic element to environments that already pose health risks to students and staff, the report says. High-poverty areas, and areas with large shares of racial minorities, are more likely to be located near highways and factories that emit toxic fumes.
“School districts and state agencies should prioritize the replacement of the oldest school buses to produce the greatest air quality and health benefits for their students,” the report’s authors write.
The report identifies a silver lining, though: New electric buses are disproportionately heading to the highest-need districts. Of the 5,612 electric school buses districts had committed to purchasing prior to Dec. 31, 2022, 43 percent are concentrated in the one-quarter of lowest-income school districts, and 68 percent are headed to the one-quarter of districts with the highest proportions of students of color.
The number of electric school buses districts have committed to purchasing has more than doubled in the last year-and-a-half to more than 12,000. Still, that number is less than 3 percent of all the school buses in the nation.
The oldest school buses are concentrated in certain states and districts
Roughly 1 in 4 school buses currently operating in the United States were built before 2010, authors found using the WRI’s database of state-level school bus statistics.
But those buses aren’t evenly distributed from state to state, or from district to district.
Researchers used Freedom of Information Act requests to get data on school buses from as many states as they could, said Brian Zepka, research manager for the Electric School Bus Initiative. But some, like Colorado and Louisiana, didn’t have any data to share, or their databases had major gaps. Some states had separate datasets for buses owned by public schools and buses districts had leased from private contractors.
The lack of consistent data is itself an equity issue, Zepka said. If policymakers don’t know where school buses are, they can’t target resources to the places that need them the most.
“Obviously for data analysis it’s best when everything merges together and is structured the same way,” Zepka said. “Each state had its data set up in a different way.”
The share of school buses built before 2010 , according to the data WRI researchers were able to collect, ranges from just half of 1 percent in Minnesota to 75 percent in Oklahoma.
Pre-2010 buses make up at least one-third of school bus fleets in 12 states—California, Georgia, Idaho, Kansas, Kentucky, North Carolina, Oklahoma, Oregon, South Dakota, Texas, Virginia, and Washington.
In six states and the District of Columbia, meanwhile, fewer than 5 percent of school buses were built before 2010. Those states were Delaware, Maryland, Massachusetts, Minnesota, New Mexico, and Rhode Island.
To assess the disparities on the district level, authors divided America’s school districts into four equal-sized quartiles, from the districts with the largest numbers of households with income below twice the poverty level, to the districts with the smallest numbers of households below that threshold—which works out to less than $62,400 for a family of four.
The concentration of pre-2010 school buses increases with each quartile, the report authors found. Slightly more than 17 percent of the nation’s pre-2010, diesel buses are located in the first quartile of districts—those with the smallest shares of low-income households. By contrast, the fourth quartile of districts—those with the highest poverty levels—are home to 30.2 percent of the nation’s diesel buses built before 2010.
The disparities are even more stark along racial lines. Authors divided school districts in four equal-sized quartiles based on the percentage of nonwhite residents within their borders, from districts with the lowest share of people of color to districts with the highest share.
Once again, the percentage of pre-2010 school buses increased with each quartile. Slightly more than 9 percent of the nation’s diesel buses built before 2010 serve the districts with the lowest share of students of color.
By contrast, 43.4 percent of the nation’s pre-2010 diesel buses are in districts with the highest shares of students of color.
Electric school bus adoption is speeding up
Advocates for improving air quality and minimizing harmful fuel emissions believe electric buses present a more sustainable alternative to diesel.
Electric buses could also save districts money on fuel over their lifespan, though they’re more expensive upfront and require new infrastructure that can be challenging to install.
“The progress is promising,” Zepka said of the growth in electric school bus adoption. The report reflects school bus adoption through December 2022; since then, the number of electric school bus slated for school districts has more than doubled to more than 12,000.
Still, that number represents less than 3 percent of the overall number of school buses nationwide. And some places are further along in the transition to electric school buses than others.
California is far ahead of the rest—districts there have either already bought or committed to buy enough electric school buses to represent 15 percent of the state’s entire fleet. Districts in Maryland, Rhode Island, Mississippi, and South Carolina currently operate or have committed to buying a number of electric buses equivalent to more than 3 percent of their fleets.
But in more than a dozen states, including Indiana, New Mexico, Ohio, and Texas, electric buses represent less than 1 percent of districts’ overall school bus fleets.
Wyoming is the only state in the nation so far where districts aren’t operating and haven’t committed to buying a single electric school bus.
Electric bus adoption growth has sped up in recent years, thanks in large part to the rollout of $5 billion in federal grants and rebates that slash hundreds of thousands of dollars from the steep cost of electric buses. Most districts that have received funds through that program have chosen to invest in electric buses, though a small share of funding recipients purchased natural gas buses or turned down the opportunity altogether.
Several states have also rolled out grant programs to expand electric school bus fleets.
But Zepka acknowledges there’s more work to be done to bring down the prices of electric school buses and to help districts understand the processes for buying and rolling them out.
