Taxi Fare Calculator to Bing Maps to help keep your cabbie in check, and it's now actually enlisted the help of some 33,000 Beijing cab drivers in an effort to further improve driving directions. More specifically, it's relying on GPS data collected from the cab drivers' cars over a period of three months, which has since been funneled into a system called T-Drive created by a team at Microsoft Research Asia. Just how big a difference can a bit of local know-how make? Apparently, about a 16 percent cut in time on average, or roughly a savings of five minutes for every 30 minutes of driving. Of course, it won't do anyone outside of Beijing much good at the moment, but there's plenty more GPS-equipped cabs out there if Microsoft ever decides to expand things.