A new study found that 6 percent of all business travel transactions in 2016 were with Uber, making the ridesharing company the most common expense, in terms of transactions. Uber grabbed the honor from Starbucks, which remains the most popular meal expense. Certify, a provider of travel and expense software for companies, analyzed 40 million expenses from 1 million business travelers for the study. The findings are a reminder of the rapid growth of ridesharing, and