Web Content Display
Graphics:
2009 and 2011 congestion scans are not available due to data issues.
2007 congestion scans are not available for the Dan Ryan Expressway because of construction at the time. Congestion scans will be produced for succeeding years as the data becomes available.
Performance Data:
Non-holiday Tuesdays, Wednesdays, and Thursdays
2008 - 2011 highway perfromance measures are not available at this time due to data issues.
2007 performance measures are not available for the Dan Ryan Expressway because of construction at the time. Performance measures for succeeding years will be produced as data becomes available.
East-bound I-94/Dan Ryan
| Measure | |
| Free-Flow Travel Time (Minutes) |
|
| Average AM Peak-Period Travel Time (Minutes) |
|
| AM Travel Time Index |
|
| Average PM Peak-Period Travel Time (Minutes) |
|
| PM Travel Time Index |
|
| AM Peak-Period 95th Percentile Travel Time (Minutes) |
|
| AM Peak-Period |
|
| PM Peak-Period 95th Percentile Travel Time (Minutes) |
|
| PM Peak-Period Planning Time Index |
|
| Congested Hours |
|
West-bound I-94/Dan Ryan
| Measure |
|
| Free-Flow Travel Time (Minutes) |
|
| Average AM Peak-Period Travel Time (Minutes) |
|
| AM Travel Time Index |
|
| Average PM Peak-Period Travel Time (Minutes) |
|
| PM Travel Time Index |
|
| AM Peak-Period 95th Percentile Travel Time (Minutes) |
|
| AM Peak-Period |
|
| PM Peak-Period 95th Percentile Travel Time (Minutes) |
|
| PM Peak-Period Planning Time Index |
|
| Congested Hours |
Web Content Display
Web Content Display
Performance Measures
The travel time index is a measure of average congestion and indicates the average extra travel time required during peak period congestion. Travel time index is a ratio of the average peak-period travel time compared to the free-flow travel time. For example, a value of 1.20 means that average peak travel times are 20 percent longer than free-flow travel times.
The planning time index is a measure of reliability and is defined as the ratio of the total time needed to ensure a 95 percent on-time arrival to the free-flow travel time. For example, a value of 1.4 means that, to arrive on-time 95 percent of the time, a traveler should budget an additional eight minutes for a trip that takes 20 minutes during off-peak, free-flow conditions.
Congested hours are an indication of how many hours per day a facility is congested. Technically, "congested hours" are defined as the average number of hours in which at least 20 percent of the vehicle miles traveled (VMT) on the instrumented segment is congested. For this measure, congestion is defined to occur when link speeds are less than 50 mph.
Data provided by IDOT, Illinois Tollway, and Traffic.com. CMAP's Todd Schmidt created the performance measures.
