It could be considered the largest transportation system in the country, moving more than 25 million passengers every weekday. Count every single vehicle used in every mass transit system in the United States, then multiply that figure by two, and that’s the rough number of vehicles in this massive fleet, which serves every corner of every state. Then consider that the vast majority of vehicles in this system haven’t seen significant updates in decades, despite rapid advances in transportation technology.

This, in a nutshell, describes the scale—and oversized opportunity for change—found within our school bus system. The estimated half million yellow buses that circle our cities, neighborhoods, and towns perform a vital service. Even urban school systems such as the New York Department of Education, where older students rely on mass transit, have a fleet of buses for younger students and those in farther-flung parts of the city.

But according to a new report, Miles to Go: Bringing School Transportation into the 21st Century, school transportation has been held back. By not embracing technology, due in large part to inertia and lack of funds, this massive part of our national transportation system has missed out on 21st-century advances that could save money, increase student safety, and even cut down carbon emissions.

“The educational system frequently describes transportation as a plumbing issue,” says Jennifer O’Neal Schiess, a principal at Bellwether Education Partners, which compiled the report. “It’s something that nobody notices unless it’s not working.”

Certainly the 55 percent of the nation’s K through 12 population, spread across the nation’s roughly 13,000 districts, would notice a difference. Many school buses on the road today predate 2007—before stricter emissions standards went into effect—only a third of school districts track their vehicles using GPS, and only 6 percent of buses nationwide run on alternative fuels instead of diesel. In an era of Teslas and Uber, school bus tech has barely budged forward.

“Innovation that’s permeated the transportation world hasn’t permeated the educational world,” Schiess says.

That’s a missed opportunity, because the potential environmental impact of change is sizable. A study by the U.S. Department of Energy’s Argonne National Laboratory found that simply by switching from industry-standard diesel to propane, a test fleet of 101 buses saved up to 50 percent on fuel costs while eliminating 770 million tons of greenhouse gas emissions annually. Switching to electric buses, according to a University of Delaware study, would save a school district $6,000 per seat, or roughly $230,000 per bus over its lifetime (a figure that also factors in the upfront cost of the new vehicle). And it’s not just money at stake. According to a 2015 study published in the American Journal of Respiratory and Critical Care Medicine, “when children ride buses with clean air technologies and/or fuels, they experience lower exposures to air pollution … and reduced absenteeism.”

Updating school transportation faces many unique challenges, according to Schiess, few more pressing than funding. Since 1980, the average transport cost per student has gone up 75 percent, a budget item, normally covered by the states, that hasn’t kept up with the cost of inflation.

Numerous layers of rules and regulations, as well as a variety of stakeholders, govern the school bus system. Federal safety regulations mandate many aspects of the system—the National Highway Traffic Safety Administration’s guidelines mention the official color “National School Bus Glossy Yellow”—while states provide part of the funding and local districts decide on operations, either running their own system, contracting to a private service, or, in the case of urban districts, offering students access to mass transit.

Density, and the changing nature of district boundaries, adds another layer of challenges. In rural districts, buses have to cover exceptional amounts of ground to get students to and from more remote rural classrooms, one reason transport can account for up to a quarter of these schools’ budgets. And in urban districts where charter schools have proliferated, school choice and the more than 3 million students attending charter schools scramble the traditional transportation paradigm, designed around neighborhood-centric schools.

Schiess and her colleagues believe that technology can help overcome many of these challenges, or at least improve performance and save districts much-needed money. Those thinking of a Lyft-like system would be getting ahead of the game, says Schiess, since many issues—including getting security checks on ride-hailing drivers up to par with current schools standards—stand in the way.

Simply tracking vehicles and ridership would offer opportunities to create more efficient routes. Investing in cleaner fuels and electric buses would save districts over the long run, with many states, including California, Ohio, Mississippi, and Texas, already offering varying types and degrees of funding for replacing older vehicles with cleaner alternatives.

“Cost increases are often born by districts,” she says. “Districts dipping into their own funds for fuel and driver wage issues, and spending more on transportation, means spending less on something else.”

On a small scale, many districts have shown the benefits of embracing new technology. In Boston, school buses have GPS, and parents have an app where they can see where vehicles are and when buses are running late. Cincinnati has begun to track ridership with ZPass, an RFID-enabled badge attached to student backpacks that lets buses track when students board or leave the bus (it can also message parents when their kids are home). John Davis, director of pupil transportation at Cincinnati Public Schools, has said the investment in data has paid off by helping to eliminate redundancies.

The holdup, according to Schiess, is often lack of capital. Cash-strapped schools have less ability to invest in technology for long-run savings when today’s bills need to be paid. She believes states should alter funding formulas to encourage innovation. Along with incentives and grants to transition to cleaner fuel, these investments could help local districts stretch already strained budgets. Florida’s system awards districts bonuses for achieving more transit efficiency.

Schiess and her colleagues have also made a more radical suggestion: Districts should take a hard look at giving away control of school busing to a regional entity, one that could maximize efficiencies and embrace technology while taking account of the way school choice is changing students’ rides to school. Perhaps the lesson here is it’s best to focus on your strengths.

“School systems aren’t experts in transportation, they’re experts in instructing kids,” says Schiess. “One thing we discovered while compiling this report is that there’s very little research on the school transportation system. We really need to try and get our arms around that.”