The Uber app is shown in this Feb. 14, 2013, file photo in Washington, D.C. (AFP)

An advocacy group for the blind is suing the app-based ride-sharing service Uber, alleging the company discriminates against passengers with service dogs.

The federal civil rights suit filed Tuesday by the California chapter of the National Federation of the Blind cites instances in California and elsewhere when blind Uber customers summoned a car only to be refused a ride once the driver saw them with a service dog. In some cases, drivers allegedly abandoned blind travelers in extreme weather and charged cancellation fees after denying them rides, the complaint said.

The complaint filed in a Northern California District Court cites one instance where a California UberX driver put a service dog in the trunk and refused to pull over when the blind passenger realized where the animal was.

On another occasion a passenger was trying to explain that his dog was not a pet but a service animal when the driver allegedly cursed at him and accelerated abruptly, nearly injuring the dog and striking the passenger’s friend, who is also blind, with an open car door.

The group said it’s aware of more than 30 times blind customers were denied rides in violation of the American with Disabilities Act and California state law.

As a result, blind passengers are confronting unexpected delays and “face the degrading experience of being denied a basic service that is available to all other paying customers,” the complaint said.

Services such as Uber are quickly supplanting traditional taxis, a service blind people rely on due to the limitations of public transportation.

The National Federation of the Blind wants Uber to educate its drivers about disability rights and punish the violators in addition to providing a way for disabled passengers to immediately register complaints when they are refused rides because of service dogs.

In a statement reported by the San Francisco Examiner, Uber said its policy is to terminate drivers who refuse to transport service animals. “The Uber app is built to expand access to transportation options for all, including users with visual impairments and other disabilities,” the statement said.

However, Uber allegedly told some passengers it can’t control what drivers do because they are independent contractors. The company advised them to let drivers know about their animals ahead of time, said the Federation, which filed suit after Uber rejected its request to negotiate a solution.

The group claims the company closely monitors and controls its drivers by managing payments and services through the app, and by assessing driver performance based on customer feedback.

In September 2013,California’s Public Utilities Commission classified UberX as a transportation provider because it functions like a taxi dispatch. The commission also said that UberX may not discriminate against the disabled, the Federation noted.

Figuring out whether to treat Uber like a traditional taxi service or something else is the subject of heated debate across the country. Taxi services are required by federal law to serve the disabled, even if drivers are independent contractors.