Chicago Traffic Tracker - Congestion Estimates by Segments
This dataset contains the current estimated speed for about 1250 segments covering 300 miles of arterial roads. For a more detailed description, go to: http://bit.ly/Q9AZAD.
The Chicago Traffic Tracker estimates traffic congestion on Chicago’s arterial streets (nonfreeway
streets) in real-time by continuously monitoring and analyzing GPS traces received from Chicago Transit Authority (CTA) buses. Two types of congestion estimates are produced every ten minutes: 1) by Traffic Segments and 2) by Traffic Regions or Zones. Congestion estimate by traffic segments gives the observed speed typically for one-half mile of a street in one direction of traffic.
Traffic Segment level congestion is available for about 300 miles of principal arterials. Congestion by Traffic Region gives the average traffic condition for all arterial street segments within a region. A traffic region is comprised of two or three community areas with comparable traffic patterns. 29 regions are created to cover the entire city (except O’Hare airport area).
This dataset contains the current estimated speed for about 1250 segments covering 300 miles of arterial roads.
There is much volatility in traffic segment speed. However, the congestion estimates for the traffic regions remain consistent for relatively longer period. Most volatility in arterial speed comes from the very nature of the arterials themselves. Due to a myriad of factors, including but not limited to frequent
intersections, traffic signals, transit movements, availability of alternative routes, crashes, short length of the segments, etc. speed on individual arterial segments can fluctuate from heavily congested to no congestion and back in a few minutes. The segment speed and traffic region congestion estimates
together may give a better understanding of the actual traffic conditions.
|Name||Socrata field name||Column name in ||Data type||Description|
|TO_STREET||_tost||_tost||Text||End street for the segment in the direction of traffic flow.|
|FROM_STREET||_fromst||_fromst||Text||Start street for the segment in the direction of traffic flow.|
|CURRENT_SPEED||_traffic||_traffic||Text||A value of -1 means no estimate is available.|
|START_LONGITUDE||start_lon||start_lon||Text||The longitude associated with the starting point of the segment in the direction of traffic flow. For two-way streets it is roughly at the middle of the half that the segment is representing. For one-way streets this is the street center line. The startin|
|SEGMENTID||segmentid||segmentid||Text||Unique arbitrary number to represent each segment.|
|STREET_HEADING||_strheading||_strheading||Text||The position of the segment in the address grid. North, South, East, or West of State and Madison.|
|DIRECTION||_direction||_direction||Text||Traffic flow direction for the segment.|
|LENGTH||_length||_length||Text||Length of the segment in miles.|
|STREET||street||street||Text||Street name of the traffic segment.|