CMAP staff has prepared an update of a report on vehicle miles traveled on the region's expressways and tollways. The report examines data through 2008. The data showed continuing moderation in historical VMT growth. Factors affecting regional expressway VMT are explored, including Tollway reconstruction and pricing changes; recent Southland road improvements; regional variations in growth and employment; motor fuel costs; changes in travel mode share; and recent high unemployment.
Recent Trends in Northeastern Illinois Expressway Vehicle Miles Traveled (VMT) (pdf, 500Kb)
CMAP staff has prepared an analysis of highway ride quality for the expressway and principal arterial systems in the Chicago region. The data is further analyzed by county-level geography. The data shows improvement in the expressway system, but deterioration in the principal arterial system. The report provides insight into current conditions, national comparisons, and historic trends.
Highway Ride Quality in the Chicago Region as of 2006 (pdf, 736KB)
Appendices (pdf, 5.6MB)
The CMAP congestion scans/performance data web is now easier to use. Each freeway segment we analyze has been assigned a separate web page. These pages are listed and linked from a window pane on the right of every segment's page.
The introductory page is at http://www.cmap.illinois.gov/scans/.
Using IDOT hourly speed data collected as part of the traffic count process, CMAP has estimated regional afternoon congestion levels on selected arterials. Broad coverage is provided for Cook County, while state highways are analyzed for DuPage, Kane, Kendall, Lake, McHenry, and Will Counties. The map depicts the ratio of the estimated afternoon peak travel time to the travel time corresponding to the 85th-percentile speed.
This map is experimental. We know that not every location's congestion shown will match users' experience. Known limitations include the limited location of the measurements. The data represents measurements on only one sample day, though many thousands of vehicles are typically measured. The map also notes other caveats. Nonetheless, the map shows the first large-scale regional portrait of arterial congestion using field data.
Questions or comments on this experimental map can be addressed to Tom Murtha, tmurtha "at" cmap.illinois.gov or 312-386-8790. Special thanks to IDOT for assistance in this project.
CMAP Afternoon Peak-Period Arterial Congestion Map (pdf, 2.5MB; viewing suggestions: on-line: 100% zoom; print: E-sized sheet).
Bridge conditions, while improving overall, vary greatly by owner and geography. This report shows regional trends and summary information for regional bridges from several perspectives. The report also explains the bridge condition rating system, allowing policy personnel and the public to understand this important issue.
This report was revised from the May, 2009 version to include an evaluation of movable bridges in the region. These bridges tend to have very high maintenance and construction costs, while the analysis shows that a large percentage of them are in need of work.
Bridge Conditons in the CMAP Region, 2007 (pdf, 5.7MB)
This page provides links to studies conducted in support of the performance measurement aspects of the CMAP Congestion Management Process. The studies provide both detailed reviews of data depicting transportation system conditions as well as information about recent trends. Having this base of information allows us to monitor the effects of transportation projects, policies, as well as land development and market factors over which we have very limited or no control.
The data available has demonstrated that infrastructure projects can alleviate highway congestion. For example, the data below show average travel times and crashes for the Eisenhower Expressway before and after a project to alleviate a bottleneck in Hillside. Travel times have improved and there have been fewer crashes (though this may not have been caused by the improvement project). We need such data, collected over long periods, to measure impacts (or lack of impacts) of projects and strategies and to find congestion and safety concerns.
Travel Times on I-290 Before and After Hillside Bottleneck Elimination: Improvement
The data below show that there was substantial improvement in travel times for some travel periods and directions for the Eisenhower. Travel time measurements were collected for 1995 and 2007 for the 31-mile segment from the Circle Interchange (I-90/94 in Chicago) to the Jane Addams Tollway (I-90) in Schaumburg.
Weekday Travel Time Summary, Before and After Bottleneck Elimination, I-290 from Circle Interchange to Jane Addams Tollway
| Direction |
Time of Day |
1995 Travel Time
(Minutes)
|
2007 Travel Time
(Minutes)
|
| East-bound |
5 am - 10 am
|
50.2
|
47.4
|
| East-bound |
2 pm - 7 pm
|
53.4
|
53.5
|
| West-bound |
5 am - 10 am
|
47.4
|
41.0
|
| West-bound |
2 pm - 7 pm
|
57.2
|
52.6
|
Source: CMAP analysis of IDOT data
Over this same time period, traffic volumes through the improvement area have increased. From 1995 to 2007, eastbound volumes at Wolf Rd. (in the project area) have risen from 78,000 to 102,000. Westbound volumes rose from 90,000 to 100,000 vehicles per day over the same time period. By contrast, traffic volumes on the Eisenhower in the still-constricted area west of Austin Boulevard have not risen much since 1995, in fact having fallen from 97,000 to 90,000 for eastbound traffic and risen from 93,000 to 94,000 for westbound traffic (source: CMAP Expressway Atlas Data).
Crashes on I-290 and I-88 Before and After Hillside Bottleneck Elimination: Equivocal Evidence
The data below show reductions in the numbers of crashes after the bottleneck elimination project. However, the data do not demonstrate cause and efffect. Indeed, the analysis of six years of crash data shows the level of reduction in crashes was no greater on the improved section of I-290 than the unimproved section of I-290. Nonetheless, the 63% reduction in crashes on I-88 on the west side of the bottleneck elimination project stands out. In addition, the number of fatalities fell from 2.3 per year before the improvement to 1.0 per year after the improvement in the improved segment. No change in fatalities was seen in the control segment.
Crash Summary, Before and After Bottleneck Elimination, I-88 and I-290
Measure
|
I-88 from Cook-DuPage County Line
to I-290 Merge (Improved Segment)
|
I-290 from Vallette Street
to 25th Avenue (Improved Segment)
|
I-290 from 25th Avenue
to Des Plaines Avenue
(Control Segment)
|
Average Crashes, 1997-1999
(Before Improvement) |
99
|
636
|
534
|
Average Crashes, 2005-2007
(After Improvement)
|
36
|
493
|
410
|
Percent Change in Crashes
from Before Period to After Period
|
-63%
|
-22%
|
-23%
|
Source: CMAP analysis of IDOT data.
The 2006 Congestion Management System Status Report (PDF 1.54MB) uses data collected from roadway sensors to analyze current operating conditions on selected expressway and tollway corridors. Forecast conditions for 2030 are also examined.
The 2002 Congestion Management System Status Report (PDF 886KB) includes an evaluation of the roadway network performance in the 1990's and projects performance measures forward to the year 2020. An historical perspective of the CMS is also presented.