There's a useful new technology now available through the Live Maps service - something called "Clearflow" - which helps alert you to bottlenecks, traffic jams, and other obstacles on the road. This new technology was developed over the course of the last 5 years by AI researchers in Microsoft Research, a project led by Eric Horvitz, who came up with the idea back in 2003 when he was stuck in traffic.
To develop the technology, Microsoft researchers collected trip data from employees who volunteered to carry GPS units in their vehicles. The end result was an algorithm for the Seattle area that was based on four years of data, 16,500 discrete trips, over 125,000 miles, and over 819,000 road segments in the Seattle region.
Now Clearflow's algorithm is available to predict traffic patterns for 72 cities in the U.S. When there is a slowdown or traffic problem, drivers will be given alternate routing info to help them get around the problem.
You can test out Clearflow for yourself on maps.live.com