The Department of Justice has filed suit against Uber over the company's practice of charging fees when drivers have to wait more than two minutes for a passenger to get in their vehicle.

The lawsuit, filed today in U.S. District Court in Northern California, says that Uber is violating the Americans with Disabilities Act by uniformly charging "wait time" fees to all passengers, and not modifying these when a passenger is disabled.

As the Associated Press reports, Uber said it was "surprised and disappointed" that the lawsuit was filed, after the company said it had been actively engaged with the DOJ on this subject.

In a statement, the company said, "Wait time fees are charged to all riders to compensate drivers after two minutes of waiting, but were never intended for riders who are ready at their designated pickup location but need more time to get into the car."

Uber added, "We fundamentally disagree that our policies violate the ADA and will keep improving our products to support everyone’s ability to easily move around their communities."

Uber said it was already refunding wait time fees if disabled passengers alerted the company that they were charged, but this apparently doesn't satisfy the ADA, according to the feds. And as the company seems to have known a lawsuit could be pending, Uber last week said all "wait time" fees were being waived in the app for any user who could certify that they were disabled.

These fees were instituted in 2016 in select cities, as the AP notes, but then spread nationwide as they clearly help Uber's bottom line — and encourage riders not to dawdle when their car is waiting.

"Uber’s wait time fees take a significant toll on people with disabilities,” said Acting U.S. Attorney Stephanie M. Hinds in a statement.

The DOJ is asking a judge to force Uber to change its policy on waiting fees, and to pay unspecified monetary damages.

As the Wall Street Journal notes, Uber shares were down 5% on Wednesday, but it's not clear if that is due to this suit.

Uber is also facing legal battles with cities, alongside competitor DoorDash, over the commission fees it charges to restaurants using the UberEats app. And in August, Prop 22, the ballot measure that Uber and Lyft bankrolled that allows drivers to remain independent contractors, was ruled unconstitutional by a California judge. Uber has already lost a similar battle in the UK, and has begun offering vacation pay and pension benefits to drivers there.