The New York Times and Sense Networks have combined efforts into building an interactive mashup of taxi tracking data with Google Maps to create an interactive heatmap of taxi stops across Manhattan Island.

Information from millions of taxi trips provides a telling record of the city’s vital signs. The map shows the average number of pickups for different times of the day and days of week, Jan. – March, 2009.

Somewhat odd that the data is from a year ago, that might possibly be a typo (and it’s actually Jan – March 2010).  You can see some interesting trends, including the basic rush hour, lunch rush, and late night traffic on Friday and Saturday night.

via Tracking Taxi Flow Across the City – Interactive – NYTimes.com.