If you're looking for a traffic data web service, you probably have not been able to find one for free. Now mapping pioneer MapQuest is beta testing a service it says provides "real time traffic information related to incidents, markets and flow."
Google keeps expanding the features of its Google Maps API, yet there's no shortage of things developers wish Google added. We know this because there is a public repository of issues. While some may be bugs, most are enhancements, desired additions to the web's most popular API.