Livery cab companies are suing the city to put the brakes on a pilot program allowing riders to hail yellow cabs using smartphones.
The suit claims the new regulations violate a law only the City Council can change, not the city's Taxi and Limousine Commission.
David Yassky, head of the TLC, says the rules allow for the change and livery groups want to keep the taxi industry and New Yorkers "in the dark ages."
The new rules were supposed to take effect Friday but the technology is not ready for installation yet.
The sides are due in court on February 28.