Microsoft has added waypoint optimization to the Bing Maps Routing API, which allows developers to create routes between driving locations. The API is ideal for delivery and transportation businesses, and the route optimization functionality is intended to address the traveling salesman problem.
As a DC-area resident, I've been one of many local developers saying that the DC Metro needs some sort of API. If anything, just to be able to build or integrate transit routes into existing apps. The wait appears over and the Washington Metropolitan Area Transit Authority now has an API.
Google has added one of the most popular features of its consumer Google Maps product to the Google Maps API. Predictive travel time is oft-used by consumers to find best routes, and avoid traffic. Now, developers have access to the feature and can integrate the functionality into third party apps.