WASHINGTON - Wave a hand, whistle, go down on your needs in the road - just three ways to hail a taxi or, in the US, a cab. Now there's another...The smartphone. And what's more, a new app(lication) can tell you which taxi to choose and give you a run-down on the driver even before you send the "come to me" signal.To be fair, they are also helping the taxi drivers.A number of new services have sprung up in recent years that enable smartphone users to locate and request a taxi with GPS. A driver will confirm he's on the way and payment will be made by the sme smartphone - no cash, no hassles.WE KNOW WHO YOU ARE Yonis Benitez, general manager in Washington for MyTaxi, a German-based company which has expanded into the US market, explained: "It gives the passenger control and incentivises the driver to provide excellent service."And it's no longer anonymous. You'll know the driver's name and the driving rating from customer reviews. Hey, imagine a star-rated taxi driver!MyTaxi was founded in 2009 in Germany but opened in the American capital, Washington, in October, just one of 30 cities worldwide where it operates. The apps, My Taxi says, promise increased business, especially in areas where vehicle and cab traffic is low. "We've been well-received in DC," Benitez said. "Our numbers have doubled month over month in terms of people joining and passengers."Across the continent, San Francisco-based Uber offers a mobile app connecting passengers and taxis in six cities, Washington among them, and operates in 27 cities worldwide with a "black car" service which, it says, costs more than taxis but less than comparable limousine services.PARTNERS ONLYUber founder and chief executive Travis Kalanick said drivers liked the system because "they make more money, they can fill out their downtime, they can invest and grow".Like other services, Uber has no cars of its own but partners with taxi and limo drivers who agree to use the app. "We are like Open Table for restaurants or Expedia for travel," he explained.Uber has faced some well-publicised regulatory hurdles (New York temporarily suspended service) while maintaining its limo operation as city officials consider regulations on the "e-hailing" of cabs.In Washington in 2012 the city council approved a measure to clear the way for app-based taxi and limo services. "The DC law is cutting edge," said Rachel Holt, Uber's manager in that city. "It's pro-innovation and a lot of cities are starting to follow."Uber, which has venture funding from Amazon's Jeff Bezos and Goldman Sachs, has been expanding globally to cities such as Paris, Melbourne and Stockholm while competition heats up in the US.30 000 DRIVERSWashington cabbie Peter Faris said he has built a three-car service with around the Uber app. "We've grown as Uber has grown in DC," he said. "There's an amazing vibe. It's hard to communicate the enthusiasm it has created. It's filled a need."Hailo, launched in London in 2011, claims to be the largest taxi app with 30 000 drivers in Boston, Chicago, Toronto and Dublin. This year it plans to launch in New York, Tokyo, Madrid, Barcelona and Washington. Jay Bregman, New York-born founder of the Britain-based company, told AFP: "The drivers have 30 to 60% downtime, depending on the city, and customers find it difficult to get a cab. This is a pattern you find all over the world."It's one of the last bastions of inefficiency."tion."