Worry about its impact on jobs, or quibble with its tactics, but give Uber this: The ride-hailing startup is taking over transportation within cities at stunning speeds.

Here's the latest evidence: Last month, Uber accounted for 47 percent of all rides expensed by employees whose companies use Certify, the second-largest provider of travel and expense management software in North America. In March 2014, Uber accounted for only 15 percent, according to a study by Certify released on April 7. 

Over that period, the amount spent on traditional taxis, limousines, and airport shuttles fell from 85 percent to 52 percent of expensed rides. Lyft, a rival ride- hailing service that caters more to consumers than professionals, currently accounts for 1 percent of business rides, the study found.