CMP Scans

Nov 8, 2013

Expressway and Tollway Performance

Freeway Segments

Select the links below to view 2016 congestion scans and corridor-level highway data for the Chicago region's expressway system. Congestion scans show average speed by milepost by time of day by direction of travel.  Explanations of other performance measures reported for the system are below.

I-55 I-55 Stevenson Expressway (Lakeshore Drive to I-294)
  I-55 (I-294 to Veterans Parkway)
  I-55 (Veterans Parkway to I-80)
  I-55 (I-80 to Grundy County Line)
I-57 I-57 (I-94 to I-80)
  I-57 (I-80 to Monee Road)
  I-57 (Monee Road to Kankakee County Line)
I-80 I-80 (Kendall County Line to Richards Street)
  I-80 (Richards Street to US 45)
  I-80 (US 45 to IL 1)
  I-80/94, Kingery Expressay (IL 1 to Indiana State Line)
I-88 I-88 Reagan Memorial Tollway (DeKalb County Line to Mitchell Road)
  I-88 Reagan Memorial Tollway (Mitchell Road to I-355)
  I-88 Reagan Memorial Tollway (I-355 to I-294)
I-90 I-90 Jane Addams Memorial Tollway (IL 31 to County Line Road, McHenry County)
  I-90 Jane Addams Memorial Tollway (IL-31 to I-290/IL-53)
  I-90 Jane Addams Memorial Tollway (I-290/IL-53 to I-190 O'Hare)
  I-90 Kennedy Expressway (I-190 O'Hare to I-94 Edens)
  I-90/94 Kennedy Expressway (I-94 Edens to I-290 Eisenhower)
  I-90/94 Kennedy Expressway (Reversible Lanes Montrose Avenue to Ogden Avenue)
  I-90/94 Dan Ryan Expressway (Local Lanes I-290 to I-90 Skyway)
  I-90/94 Dan Ryan Expressway (Express Lanes I-55 to I-90 Chicago Skyway Split)
  I-90 Chicago Skyway (I90/94 Dan Ryan to Indiana State Line)
I-94 I-94 Tri-State Tollway from (IL 173 to I-294/I-94 Edens/Tri-State Split)
  I-94 Edens Spur (I-294 Tri-State Tollway to I-94/US 41 Edens Expressway)
  I-94 Edens Expressway (I-94 Edens Spur to I-90 Kennedy Expressway)
  For I-94 segments co-running with I-90, see I-90 segments above.
  I-94 Dan Ryan Expressway (I-90 Chicago Skyway to I-57)
  I-94 Bishop Ford Freeway (I-57 to I-80/I-294 Kingery Expressway)
  I-80/94 Kingery Expressway (IL 1 to Indiana State Line)
I-190 I-190 (Chicago O'Hare International Airport to I-90)
I-290 I-290 (I-90/IL-53 Jane Addams to I-355 Veterans)
  I-290 (I-355 to I-88 Reagan)
  I-290 Eisenhower Expressway (I-88 Reagan to I-90/94 Byrne Interchange/Ryan)
I-294 I-294 Tri-State Tollway (I-94 Edens Spur to I-90 Jane Addams)
  I-294 Tri-State Tollway (I-90 to I-55)
  I-294 Tri-State Tollway (I-55 to I-94/Bishop Ford Freeway)
I-355 I-355 Veterans Memorial Tollway (I-290 Eisenhower to I-88 Reagan)
  I-355 Veterans Memorial Tollway (I-88 Reagan to I-55)
  I-355 Veterans Memorial Tollway (I-55 to I-80)
IL 53 IL-53 (Lake-Cook Road to I-290/I-90)
IL 390 IL 390 Elgin-O'Hare (US 20 Lake St to Proposed I-490 O'Hare Western Access)
IL 394 IL-394 (I-80 to US 30)
US 41 US 41 Lake Shore Drive (Hollywood Avenue to Jackson Boulevard)
  US 41 Lake Shore Drive (Roosevelt Road to Marquette Drive)


Key to Highway Measures

As part of CMAP's Congestion Management Process, select performance measures for the regional freeways have been created from five minute speed data obtained from the Illinois Department of Transportation (IDOT) and These performance measures include congestion scans, travel time index, planning time index, and congested hours.

The Chicago region traffic congestion scans were created by averaging five minute speed data obtained from freeway loop detectors, radar detectors, and mobile technology data. The traffic scans display average speed on a freeway corridor as a function of time of day (the x-axis) and location (the y-axis) along a freeway corridor.

Crash scans show the rate of total highway crashes per 100 million vehicle-miles traveled (VMT) for 1/10 mile segments.  The purpose of these crash scans is to show highway planners and system managers how crashes are related to congestion.  Understanding where crashes are concentrated can help planners and engineers focus on improving those locations with the worst performance.  Solutions may involve safety improvements, but are just as likely to involve traffic operations or highway geometry improvements.

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 HERE. CMAP's Todd Schmidt created the performance measures.

Quarterly Congestion Report

The quarterly congestion report (QCR) provides a snapshot of highway traffic congestion on the region's expressways and tollways. The report uses consistent, user-oriented measures to allow comparing congestion at one location against another. The report also identifies trends by comparing with previous quarters. Currently, the quarterly report tracks congestion measures only, but will expand later to include metrics related to freight, incident, and construction activity.


2016 Quarter 4



Click here to view full report.


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