Microsoft today updated Bing Maps with a new routing engine that will make calculating driving directions on the service faster and smarter. Based on theoretical work done by a team at Microsoft Research, the Bing team today switched out its old routing algorithm for its own creation earlier today. According to Microsoft, this new algorithm will calculate routes about twice as fast as the previous one. In addition, developers will now also be able to request up to three alternate routes with a single request (oddly enough, Bing Maps itself does not present you with alternate routes in the way the mapping app on the iPhone does, for example).
While calculating driving directions seems like a pretty mundane task to most of us who use these services virtually every day, routing algorithms are actually pretty complicated. Until now, Microsoft used a modified version of Dijkstra's algorithm.
As the Microsoft Research team notes in its paper, though, most of the existing algorithms focused mostly on driving times (especially in the pre-processing stage that turns the map data into bits that the algorithm can use), but didn't take into account that users now expect walking and biking directions, as well as other features like avoiding traffic jams and U-turns etc. Microsoft then went out to develop a system that makes it faster and easier to incorporate real-time traffic data, for example, and can even handle personalized driving directions (say you drive a truck with height and weight restrictions).
For all the gory details about how this works, have a look at the Microsoft Research paper. As a user, though, the main advantage here is speed, as well as the promise of more personalized routing directions in the future.