Hailing a cab in Calgary has now switched from the wave of an arm to the tap of a thumb.

U.S.-based tech company Uber, which launched in Montreal last week and Toronto last year, is test-driving its smartphone taxi app in Calgary this week. After setting up an account with a credit card, the app will dispatch a cab to your current location, automatically billing you when you arrive at your destination.

"No money exchanges hands. It's all done electronically," said Uber spokesman Andrew Noyes.

'No money exchanges hands. It's all done electronically.'- Andrew Noyes, Uber

The company is working with existing providers of upmarket sedan-limousine cars, where drivers must charge a minimum of $78 a ride under Calgary's taxi bylaw.

Noyes says the company picked Calgary as its next market after hearing about the long waits for cabs. In the past three decades, the number of taxis has changed very little. In 1986, the city capped the number of taxi plates at 1,311 taxi plates; today there are 1,466, despite the population nearly doubling.

Noyes says while Uber will not add any new cars on the road, it should improve wait times, as its software can predict areas of greater demand in a city and dispatch cars accordingly.

Noyes says Uber plans to lean on city hall to try to loosen the regulations on limousine service, especially the $78 minimum.

In an attempt to build buzz, Uber is offering free rides this week through its service.

"We would love for city hall to take a ride over the next five days and see how they like it," said Noyes.