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I-55 (I-294 to Veterans Parkway) Congestion and Crash Scans

The Chicago region traffic congestion scans were created by averaging five minute speed data obtained from freeway loop detectors, radar, 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.  

Congestion Scans

I-55 from I-294 to Weber Road Congestion Scan, 2016.  Showing average speed by milepost by time of day by direction of travel.

Download high-resolution PDF (all vehicles, as shown above)

Download high-resolution PDF (trucks only)

 

I-55 from I-294 to Veterans Parkway Congestion Scan, 2011. Showing average speed by milepost by time of day.

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I-55 from I-294 to Veterans Parkway Congestion Scan, 2009. Showing average speed by milepost by time of day.

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I-55 from I-294 to Veterans Parkway Congestion Scan, 2007. Showing average speed by milepost by time of day. 

Download hi-res PDF

Crash Scan

I-55, Stevenson Expressway from I-294 to Veterans Pkwy. Crash Scan, 2008-12. Showing number of crash rates per 100 million vehicle miles traveled.

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Performance Data

Non-holiday Tuesdays, Wednesdays, and Thursdays:

 

South-bound I-55

 

Measure 2007 2008 2009 2010 2011
Free-Flow Travel Time
(Minutes)
11.42 11.42 11.33 11.42 11.40
Average AM Peak-Period
Travel Time (Minutes)
15.02 14.70 14.13 14.36 14.60
AM Travel Time Index 1.31 1.29 1.25 1.26 1.28
Average PM Peak-Period
Travel Time (Minutes)
22.92 20.58 18.77 18.07 19.04
PM Travel Time Index

2.01

1.80

1.66

1.58 1.67
AM Peak-Period
95th Percentile Travel Time
(Minutes)

17.17

16.64

15.73

16.15 16.02

AM Peak-Period
Planning Time Index

1.50

1.46

1.39

1.41 1.40
PM Peak-Period
95th Percentile Travel Time
(Minutes)

36.16

30.37

27.51

24.44 27.14
PM Peak-Period
Planning Time Index

3.17

2.66

2.43

2.14 2.38
Congested Hours

12.28

11.80

10.58

10.94 11.24

 

North-bound I-55

 

Measure

2007

2008

2009

2010 2011
Free-Flow Travel Time
(Minutes)

11.40

11.44

11.44

11.52 11.44
Average AM Peak-Period
Travel Time (Minutes)

21.24

19.21

20.28

19.30 19.60
AM Travel Time Index

1.86

1.68

1.77

1.68 1.67
Average PM Peak-Period
Travel Time (Minutes)

19.57

19.37

16.80

17.62 17.26
PM Travel Time Index

1.72

1.69

1.47

1.53 1.51
AM Peak-Period
95th Percentile Travel Time
(Minutes)

35.86

32.87

35.24

31.78 30.57

AM Peak-Period
Planning Time Index

3.15

2.87

3.08

2.76 2.67
PM Peak-Period
95th Percentile Travel Time
(Minutes)

38.41

38.82

30.25

31.01 28.68
PM Peak-Period
Planning Time Index

3.37

3.39

2.64

2.69 2.51
Congested Hours

11.57

11.19

9.87

10.84 10.85
 

 

About the Data

Data provided by IDOT, Illinois Tollway, and HERE.

2016 scans were prepared using the RITIS system, developed by the University of Maryland's CATT Lab.  Data comes from the National Performance Measure Research Dataset (NPMRDS), a HERE dataset made available to states and MPOs through the Freight Management and Operations Program of the Federal Highway Administration.  
 
Notice: This material is based upon work supported by the Federal Highway Administration under contract number DTFH-13-C-00012. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not reflect the views of the Federal Highway Administration.
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