Perhaps you’ve heard of a little thing called the Americans with Disabilities Act, better known as the ADA, a federal law passed in 1990 that prohibits discrimination against people with disabilities. It’s a very famous law! But in New York City, the Metropolitan Transportation Authority, which runs the subways and buses among other things, has basically been ignoring it since the day it was signed. And this week, following a lawsuit, a federal judge .

This is good news for one of the least-friendly cities on earth to people with disabilities. But before we get to why a judge finally intervened, it’s important to understand how we got here in the first place.

Installing elevators in every subway station (there are nearly 500 of them) is expensive. The subway is very old and many stations are in super-dense urban environments with complicated infrastructure like power, gas, communications cables, and water mains below street level. The MTA typically spends tens or hundreds of millions of dollars per station to install elevators, depending on the specs of each station. (This is a lot, , but the MTA’s inability to do or build anything in a cost-effective manner is far too big of a bite to chew here.)

Technically, under the ADA, the MTA would have to install elevators and other accessible infrastructure at every station it renovated—even if it was just putting in a new handrail. The MTA didn’t do this. Only are ADA-compliant, meaning most of the subway is off limits to folks with disabilities.

Essentially the MTA said it would be too expensive to build all those elevators, so activists and local politicians decided to take what they could get and to make 100 of the 472 stations fully accessible by 2020 that exempted the agency from having to comply with every aspect of the ADA.

But that doesn’t mean the MTA was legally justified in completely ignoring the ADA, which brings us to the lawsuit in question. The lawsuit was filed in 2016 after the MTA renovated the stairs at the Middleton Road stop in the Bronx but did not add elevators.

This renovation, the lawsuit filed by disability rights activists argued, triggered the MTA’s requirement to fully upgrade the station, which the MTA didn’t do. That same year, the MTA launched a program called to spend $1 billion to renovate 19 stations, which as installing mostly cosmetic upgrades such as fancier lighting, more digital information screens, and USB ports. Of course, the program did not include installing elevators.

Last March, in the lawsuit because the MTA asked for $21 million from the Federal Transit Administration for the project—yes, it costs the MTA more than $21 million to replace stairways, which is as good of a snapshot as any on —by arguing that elevators at that location were “technically infeasible.” That technical infeasibility argument is the only way the MTA can get federal transportation dollars for a station renovation without having to actually install elevators.

The problem with this, according to the feds: it wasn’t true. It was technically feasible to install elevators; the MTA just didn’t want to pay for it (in 2015, the MTA that if they wanted elevators to be a part of a $400,000 station renovation, they should find $15 million to give the MTA to do it). This week, and further ordered the MTA to quit coming up with excuses not to install elevators and to install elevators when the ADA requires it.

These decades of punting on subway accessibility have put the current MTA administration in a real bind. The ADA requires the MTA to still provide transportation services for New Yorkers with disabilities, which, in the absence of elevators in the subway, means driving 144,000 people around the city.

The MTA spends about $450 million a year on paratransit, most of which is on a service called Access-A-Ride. This service . Customers have to book their rides at least 24 hours in advance—think about what your life would look like if you had to book all your transportation 24 hours in advance—and are all-too-often taken on multiple-borough tours only to arrive at their destination horrifically late. Due to these limitations, very few Access-A-Ride customers book more than one round-trip per day, if any.

The lone bright spot here has been a pilot program launched in 2017 called e-hail. This allowed 1,200 Access-A-Ride customers to use the on-demand apps that hail the accessible vehicles in the city’s taxi fleet, with the MTA picking up the ride cost, so they no longer have to book rides 24 hours in advance and can get to where they need to go with some modicum of normalcy. Amazingly, this is actually about 50 percent cheaper for the MTA on the per-ride basis than Access-A-Ride.

The “problem” is that those 1,200 customers are no longer disincentivized to move about their city by being beholden to a grotesquely unfair system. So even though the MTA is spending far less on a per-ride basis, they’re spending more overall on paratransit because . As a result, the future of the e-hail pilot is very much in doubt because—wait for it—the MTA says it costs too much.

Today, the pilot program—which, let me emphasize, is the biggest service improvement the MTA has ever enacted and one of the only programs for which it has received universal acclaim—will be shut down because it’s not fiscally sustainable.

The MTA subsequently , saying the pilot program will expire in April as planned and that no decisions have been made about its future. Further, Andy Byford, who took over as head of the MTA’s subways and buses division in January 2017, has made improving accessibility one of the four pillars of his tenure and .

It’s certainly true that the MTA subsidizing cab rides is not a long-term solution, but by that token neither is Access-A-Ride, a program that has existed for decades and is even less efficient.

So it’s with this history in mind that the federal judge’s decision this week is so important. “The MTA is now on notice that whenever it renovates a subway station throughout its system so as to affect the station’s usability, the MTA is obligated to install an elevator, regardless of the cost, unless it is technically infeasible,” warned U.S. Attorney Geoffrey S. Berman.

For the first time, an authority higher than the MTA itself is telling them that it’s too expensive is no longer an excuse. And that’s good news for everybody trying to get around in America’s biggest city, something that historically has been extremely hard.