Web Content Display

To view performance measures and congestion scans for freeways in the Chicago region, visit our scans page.

View the list of topics on this page (below the regional summary of key congestion measures).

To view highway safety data, visit our safety page.

2012 Expressway Atlas

CMAP has prepared a draft 2012 Expressway Atlas.  The 2012 Expressway Atlas provides a desktop reference of average annual daily traffic (AADT) volumes and other traffic system statistics, as well as graphics, for northeastern Illinois.  The data included in the Expressway Atlas is useful as baseline data for traffic planning, but also includes historical data extending back to 1984.  

The Atlas provides information for Illinois Department of Transportation (IDOT) expressways.  The Illinois Tollway maintains an annual Traffic Data Report that is available upon request from the Tollway.

The 2012 Expressway Atlas is the first Expressway Atlas produced by the Chicago Metropolitan Agency for Planning (CMAP) and is also the first atlas produced for IDOT expressways and ramps in over a decade.  The previous six expressway travel atlases were produced by the Chicago Area Transportation Study (CATS) in 1965, 1972, 1984, 1990, 1995, and 2001.

2012 Expressway Atlas:  Annual Average Daily Traffic on Northeastern Illinois Expressways (PDF, 25 MB, entire document)

The document is also available in parts:

2012 Expressway Atlas, Part 1  (pdf, 5MB, Contents, Introduction, Methods, System Data).

2012 Expressway Atlas, Part 2  (pdf, 22 MB, Daily and Monthly Factors, AADT Tables, and Hourly Percent Tables, by Expressway Segment)

2012 Expressway Atlas, Part 3 (pdf, 4MB, Traffic Flow Graphics by Expressway Segment)

 

Key Regional Transportation Measures:
 

Key Transportation Measures
Congestion-Related Measures 2007 2008 2009 2010 2011 2012
Travel Time Index,
Limited Access Highways,
Second Quarter
1.50 1.46 1.32 1.39 1.34 1.32
The Travel Time Index is a measure of congestion.  It's defined as the ratio of peak-period travel time to free-flow travel time. Peak-period is 6-9 am and 4-7 pm.  More information, including links to measurements for individual facilities, is at http://www.cmap.illinois.gov/cmp/scans

Congested Hours per Day,

Limited Access Highways,
Second Quarter

12.40 13.45 10.05 9.39 8.07 8.38
Congested Hours per Day is another measure of congestion.  This measure is defined as the average number of hours per day during which at least 20% of the vehicle-miles traveled on the instrumented segment is traveling at congested speeds (less than 45 mph).  More information, including links to individual facilities, is at http://www.cmap.illinois.gov/cmp/scansGO TO 2040 establisehd a target of "no growth" in congested hours from 2010 to 2040.
Vehicle Miles Traveled (VMT) per Year per Capita (AADT-Based Measure) 7,158 7,069 7,031 6,960 6,743  
VMT per Year per Capita is a measure of travel demand.  Higher VMT sometimes explains increased congestion levels.  For this method, IDOT calculates total VMT by factoring traffic counts on regional roads collected as part of a regular data collection program.  This data includes all travel, including through trips and external travelers.  See http://www.dot.il.gov/adttravelstats.html.  The data is normalized using intercensal population counts from the US Census Bureau.  Expressway VMT trends through 2010 are discussed below.
VMT per Year per Household (Odometer-Based Measure)         10,939  
This VMT measure is based on odometer readings collected as part of the IEPA vehicle inspection and maintenance process. The annual miles traveled between inspections is multiplied by the number of vehicles per household, then divided by the number of households to arrive at VMT per household.  This measure will include external travel by local households.  There is no easy way to calculate the external travel of local residents, but the National Household Travel Survey indicates that 25.6% of passenger vehicle trips are greater than 50 miles, one-way.
Motor Vehicles per Household 1.627 1.620 1.598 1.605 1.569  
Motor Vehicles per Household is a measure of travel demand.  This measure is derived from the US Census Bureau's American Community Survey.  The American Community Survey reports the total household vehicles and the number of households by geographic area.
Unlinked Transit Passenger Trips per Capita 0.202 0.211 0.205 0.202 0.208  
Unlinked Transit Passenger Trips per Capita is a measure of transit use, which may abate highway congestion.  Transit trip data comes from the National Transit Database.  Intercensal population estimates are from the US Census Bureau.
 
System Reliability Measures 2007 2008 2009 2010 2011 2012

Planning Time Index,

Limited Access Highways,

Second Quarter

2.03 1.95 1.72 1.74 1.70 1.65
The Planning Time Index is a measure of travel time reliability.  It is the ratio of the total time needed to ensure a 95% on-time arrival to the free-flow travel time. 
Average Weekday Motorist Delay at Highway-Rail Grade Crossings 10,982 (2002) - - - 7,817  
This measure indicates the level of delay associated with railroad grade crossings.  The measure takes into account such factors as highway volumes, train volumes (freight and passenger), train speeds (freight and passenger), and proximity to yards and passenger stations, both of which add to delay. GO TO 2040 established targets of <10,000 hours per weekday by 2015, and <5,500 hours per weekday by 2040.
Transit Metra On-Time Performance 95.7% 95.4% 95.7% 95.9% 93.6% 95.8%
This is a measure of the on-time performance of Metra commuter rail services.  This is calculated by Metra.  For more information, see the Metra website.
Transit Pace On-Time Performance - 68.4% 71.5% 70.9% 74.2%  
This is a measure of the on-time performance of Pace suburban bus services.  This is calculated by Pace.  For more information, see the Pace annual budgets.
Transit CTA Rail Delays of 10 Minutes or More - 90 67 70 92 105
This is a measure of the on-time performance of Chicago Transit Authority rail services.  This is a 12-month average of values calculated by CTA.  For more information, see the CTA Performance web page.
Transit CTA Bus Percent of Bunched Bus Intervals - 3.3% 2.3% 2.3% 2.3% 2.7%
This is a measure of the on-time performance of Chicago Transit Authority bus services.  This is a 12-month average of values calculated by CTA.  For more information, see the CTA Performance web page.
 
Infrastructure Condition Measures 2007 2008 2009 2010 2011 2012
Principal Arterials of Acceptable Ride Quality (IRI < 170) 61.9% (2006) - - 68.5% 70.6%  
Acceptable ride quality is measured by the International Roughness Index.  It is the change in longitudinal profile, measured as meters per kilometer.  A value over 170 is considered unacceptable. GO TO 2040 sets targets of >65% by 2015 and >90% by 2040.
Structurally Deficient Bridges, Percent of All Bridges 11.0% 11.0% 10.3% 9.8% 9.9% 9.7%
"Structurally deficient" is a measure of bridge structural health.  This information is generated from detailed structural evaluations gathered as part of bridge inspections.  The data is maintained in the National Bridge Inventory.  The year indicates the year of the file, reflecting data collected through the previous year.
Bridges "Not Deficient," Percent of All Bridges 66.5% 66.9% 67.2% 67.3% 68.3% 68.7%
"Not Deficient" measures bridges that are neither "structurally deficient," as shown above, nor "functionally obsolete."  "Functionally obsolete" bridges do not meet current design standards (for criteria such as lane width). GO TO 2040 sets regional targets of >70% by 2015 and >80% by 2040.
             

 

System Performance Data On this Page or on MetroPulse:

System Reliability:
- Transit On-Time Performance Charts
- See the scans page for the "planning time index" reliability measure for individual freeways.

System Operations:
- Travel Time Index (regional summary - opens MetroPulse window)
- Congested hours (regional summary - opens MetroPulse window)
- See the scans page for the "travel time index" and "congested hours" measures for individual freeways.
- Passenger Miles Traveled by Vehicle Revenue Hour, 2000 - 2010
- Arterial Congestion Estimate 2010 Map
- Speed Limit Compliance on Arterials and Collectors in the Chicago Region, as of 2007
 - Motorist Delay at Highway-Rail Grade Crossings, 2002-2011 (opens MetroPulse Window)

Travel Choices:
- Means of Transportation to Work, Chicago Region, 2000 - 2010
- Household Vehicle Availability in the Chicago Region, 2000 - 2010
- Inter-City Travel Destinations by Distance and Mode
- Off-Peak Travel by Vehicle Class, 2007-2011
- Vehicle Miles Traveled on Expressways in the Chicago Region
- Trips Underway by Time of Day by Travel Mode and Trip Purpose
- Chicago Regional Household Travel Inventory: Mode Choice and Trip Purpose for the 2008 and 1990 Surveys

System Maintenance:
- Regional Bridge Conditions Report
- Highway Ride Quality in the Chicago Region as of 2006
- Intermodal Freight Connectors: Pavement Condition 2009 Update

 

Means of Transportation to Work, Chicago Region, 2000-2010.

CMAP compiles regional indicators, including several transportation system performance measures.  CMAP recently compiled information about the means of transportation to work for workers in the 7-county Chicago region.  Following are some tables that show how the region's travelers are changing their mode of travel to work.

Driving alone.  The first table shows the percent of travelers driving alone to work for Chicago, suburban Cook County, and the collar counties.  The table shows that the percent of workers driving alone to work remained fairly constant over the 10-year analysis period.  Driving alone to work has the highest mode share in the collar counties.

Driving Alone Mode Share, Journey to Work, Metropolitan Chicago, 2000 - 2010
Area 2000 2005-2007 2008-2010
Chicago 50.13% 52.15% 50.39%
Suburban Cook County 75.71% 75.86% 75.82%
Collar Counties 79.79% 79.91% 79.33%
Seven-County Region 69.09% 70.22%

69.38%

Prepared by CMAP.  Source: US Census Bureau

Carpooling.  The second table shows that the percent of travelers carpooling to work in the Chicago region continued to decline from 2000 to 2010.  The decline was steepest in Chicago, where carpooling rates have been higher than the rest of the region.

Carpool Mode Share, Journey to Work, Metropolitan Chicago, 2000 - 2010
Area 2000 2005 - 2007 2008 - 2010
Chicago 14.49% 10.61% 9.88%
Suburban Cook County 10.03% 9.10% 9.06%
Collar Counties 8.95% 8.48% 7.99%
Seven-County Region 11.05% 9.32% 8.89%

Prepared by CMAP.  Source: US Census Bureau

Public Transportation.  The third table below shows that, over the ten-year analysis period, public transportation mode share stayed relatively stable in the suburbs, and rose modestly in the City of Chicago.  Public transit use remains highest in the City of Chicago.

Public Transportation Mode Share, Journey to Work, Metropolitan Chicago, 2000 - 2010
Area 2000 2005 - 2007 2008 - 2010
Chicago 25.27% 25.90% 26.67%
Suburban Cook County 8.18% 8.59% 8.06%
Collar Counties 4.70% 4.38% 4.55%
Seven-County Region 12.38% 12.21% 12.40%

Prepared by CMAP.  Source: US Census Bureau

Bicycle.  The fourth table shows the work trip mode share for bicycles.  Bicycling remained a very small share of trips to work, but grew rapidly over the analysis period, particularly in Chicago.

Bicycle Transportation Mode Share, Journey to Work, Metropolitan Chicago, 2000 - 2010
Area 2000 2005 - 2007 2008 - 2010
Chicago 0.50% 0.92% 1.18%
Suburban Cook County 0.28% 0.34% 0.45%
Collar Counties 0.20% 0.29% 0.27%
Seven - County Reigon 0.32% 0.49% 0.61%

Prepared by CMAP.  Source: US Census Bureau

Worked at Home.  The share of workers working at home rose substantially over the analysis period in both Chicago and the suburbs.  The highest mode share for working at home is in the collar counties.

Share of Workers Who Worked at Home, Metropolitan Chicago, 2000 - 2010
Area 2000 2005 - 2007 2008 - 2010
Chicago 2.36% 3.38% 4.30%
Suburban Cook County 2.77% 3.14% 3.61%
Collar Counties 3.61% 4.37% 4.98%
Seven-County Region 2.95% 3.70% 4.37%

Prepared by CMAP.  Source:  US Census Bureau

Two other general categories of the means of transportation to work, walking and "other means," are not shown here.  However, detailed information for these modes and for the modes above are included in detailed journey to work tables.  The tables include data for individual counties and seven municipalities.

The data above was prepared by CMAP in July, 2012.  Source: US Census Bureau, American Community Survey, 3-year samples 2005-07 and 2008-10, Table B08006; Year 2000 Decennial Census Table P030.  This data is based on a sample and is subject to error.

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Household Vehicle Availability in the Chicago Region, 2000-2010

CMAP staff recently compiled information regarding household vehicle availability.  Following is a table that shows vehicle availability trends for the period 2000 to 2010.  The data shows that the long-term increase in household vehicle availability has recently flattened out.  

Average Vehicles per Household, 2000 to 2010
Area 2000 2005 - 2007 2008 - 2010
Chicago 1.07 1.15 1.12
Suburban Cook County 1.67 1.73 1.73
Collar Counties 1.95 1.97 1.96
Seven-County Region 1.53 1.62 1.61

Prepared by CMAP. Source:  US Census Bureau

More information is available in detailed vehicle availability tables.  These tables include the percent of households with zero, one, two, and three or more vehicles by county and for selected municipalities.

For a more in-depth report that includes analyses of the social and economic factors influencing vehicle ownership rates, see the following paper, which includes data analyses through 2007: Vehicle Availability in the Chicago Region, 2007  (pdf, 1.2MB)

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Inter-City Travel Destinations by Distance and Mode

CMAP recently summarized inter-city transportation timetables for trips from Chicago.  The timetable trips are aggregated by mode and distance for each destination, as shown below.

Number of Intercity Destinations from Chicago by Mode of Travel and Mileage Range,
Spring 2012
Mileage Range Commercial Passenger Air Carriers Destinations Amtrak Destinations Express Bus Destinations
1-250

29

22 22
251-500 31 23 12
501-1000 63 12 0
1001-2000 46 6 0
2001-4000 9 0 0
4001-6000 18 0 0
6001-8000 8 0 0
Total Destinations 204 63 34

Source: Compiled by CMAP, using carriers' timetable data.  Air carrier data only includes non-stop flights.  Amtrak and express bus destinations include only destinations with more than 20,000 population and no layover longer than 20 minutes.  Some seasona variation exists, particularly in air travel destinations.

As NATO leaders convene in Chicago, it is worth noting that nine NATO capitals (in addition to Washington) have non-stop air service to Chicago.  Fourteen non-stop destinations in European NATO countries and ten destinations in Canada stretch from Istanbul to Vancouver, 24 from among the 204 total airline non-stop destinations tabulated from current timetables.

A strong air transportation system provides global access for the region's businesses.  To complement air travel, rail and bus transportation, particularly for shorter distances, allow travelers choices regarding prices, travel time, terminal dwell time, and destinations.  As can be seen in the table above, most express bus trips are less than 250 miles; most Amtrak destinations from Chicago are less than 500 miles.  While air carriers compete for these relatively short trips, the carriers also serve travel destinations spanning the globe; non-stop destinations like Hong Kong and Shanghai can be more than 7000 miles away.

Support for multi-modal transportation choice can include support for air travel, including ground access, terminal improvements, and airside capacity.  Some of these improvements, like I-190 and the Elgin-O'Hare andWest O'Hare Bypass, are among the major capital projects in the GO TO 2040 Comprehensive Regional Plan.  In addition, multi-modal intercity travel improvements are programmed in CREATE (through its Passenger Corridor projects), the proposed West Loop  Transportation Center, and the CMAQ-programmed intercity bus terminal.  Improvements to intercity rail services recently funded by the federal and state governments will also provide more passenger choices and allow optimal usage of the infrastructure available.

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Off-Peak Travel by Vehicle Class, 2007-2011

Recently compiled data includes Vehicle Classification by Time of Day, showing the percent of vehicle volumes off-peak.  The data shows that both single-unit and multi-unit trucks are somewhat more likely to travel off-peak than passenger vehicles.  However, the data do not reveal a clear trend over time toward either greater or lesser off-peak travel.

Percent of Vehicle Travel Off-Peak, by Vehicle Class, Chicago Region, 2007-2011
Type of Facility Class of Vehicle 2007 2009 2010 2011
Arterials Passenger Vehicles 60.20 61.06 N.A. N.A.
Single-Unit Truck 63.60 65.00 N.A. N.A.
Multi-Unit Truck 61.44 62.04 N.A. N.A.
Illinois Tollway Single-Unit Truck N.A. 66.94 65.41 66.19
Multi-Unit Truck N.A. 70.85 69.07 70.59

"Peak Period" is defined as 6am to 9am and 4pm to 7pm Monday through Friday.  "Off-peak" is all other times.  Prepared by Chicago Metropolitan Agency for Planning, 2012.  Sources: Illinois Tollway traffic counts via traffic.com; Illinois Department of Transportation Traffic County Program.  N.A. means not available at this time.

Trucks contribute to regional traffic congestion, but are also negatively impacted by such congestion (see animations showing truck travel speed by milepost, time of day, and day of week for I-90 at CMAP's Freight Snapshot page).  Many truckers would prefer to reduce travel costs and travel time by traveling off-peak, but there are constraints forcing many truckers to travel during the peak period.  These constraints include requirements of either shippers or receivers (who may not be open for business or set up to allow unattended deliveries overnight), but may also include regulatory requirements that require day-time travel. Such regulations may include truck permits or land-use regulations restricting overnight deliveries.  Lifting such regulations, where appropriate, may reduce the costs of making and consuming things in the region by reducing transportation costs.  In addition,  having more trucks travel off-peak might reduce highway congestion. 

CMAP has also prepared complete table showing percent of travel off-peak by vehicle class and county for the period 2007-2011.

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Passenger Miles Traveled by Vehicle Revenue Hour, 2000 - 2010

This data, from the National Transit Database, is a regional indicator derived from information provided by transit agencies on an annual basis to the Federal Transit Administration.  The measure is sensitive to both operational efficiency and passenger travel.

Highlights from the most recent data for 2010 indicate that, despite curtailed service, Chicago Transit Authority (CTA) rail travel increased, resulting in an increase from 321.8 passenger miles travelled per vehicle revenue hour in 2009 to 372.6 in 2010.  On the other hand, a decrease in ridership from 2009 to 2010 resulted in the measure falling from 1188.7 to 1151.1 for Metra rail operations.  For bus operations, the performance measure rose from 105.5 to 118.8 amid curtailed bus operations at CTA, but fell from 140.9 to 133.8 for bus services operated by Pace Suburban Bus Service.

Passenger Miles Traveled per Vehicle Revenue Hour, Selected Directly-Operated Services

System, Mode 2000 2005 2008 2009 2010
Chicago Transit Authority Heavy Rail 371.6 307.3 310.5 321.8 372.6
Chicago Transit Authority Bus 124.2 115.9 110.8 105.5 118.8
Metra Commuter Rail 1,361.4 1,251.2 1,264.5 1,188.7 1,151.1
Pace Bus 144.4 163.6 167.5 140.9 133.8

 

Additional passenger miles traveled per vehicle revenue hour data is available in a pdf-format summary or in Microsoft Excel, showing all modes and services for regional agencies from 2000 to 2010.  This data is also available on MetroPulse at www.metropulsechicago.com

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CMAP Arterial Congestion Estimate 2010 Map (October, 2011)

Using IDOT hourly speed data collected as part of the traffic count process, CMAP has estimated regional afternoon congestion levels on monitored roadways. Broad coverage is provided for Cook, McHenry, and Kane Counties, while state highways are monitored for DuPage, Kendall, Lake, and Will Counties. The map depicts the travel time index, which is the ratio of the estimated afternoon peak travel time to the free flow travel time. The map also includes a table of the AM and PM travel time index for each county in the region weighted by vehicle miles traveled. All monitored roadways were used in this analysis.

This map displays the most complete regional arterial data set available. However, not every location's congestion shown will match the user's experience. Known data 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.

2010 CMAP Arterial Congestion Estimate Map - 2010 Update (pdf, 3.8 MB; viewing suggestions: on-line: 100% zoom; print: E-sized sheet).

2009 Map (2006-2007 data): CMAP Afternoon Peak-Period Arterial Congestion Map  (pdf, 2.5MB; viewing suggestions: on-line: 100% zoom; print: E-sized sheet).
 

CMAP Arterial Congestion Estimate by Township 2010 Map (October, 2011)

Using IDOT hourly speed data collected as part of the traffic count process, CMAP has estimated regional morning and afternoon congestion levels by township on monitored arterials. The map depicts the AM (6:00-8:59 am) and PM (4:00 – 6:59 pm) peak period travel time indices. The travel time index is the ratio of the estimated peak travel time to the free flow travel time weighted by vehicle miles traveled. The map also includes a table with the AM and PM travel time index for each county in the region weighted by vehicle miles traveled. Only monitored arterial streets were used in this analysis.

2010 CMAP Arterial Congestion Estimate by Township Map - 2010 Update  (pdf, 1.6 MB)

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Vehicle Miles Traveled on Expressways in the Chicago Region (August, 2011)

This brief paper summarizes vehicle miles travelled (VMT) trends and identifies factors that may have caused recent changes in VMT on expressways in metropolitan Chicago.  The paper analyzed trends up to 2009.

Vehicle Miles Traveled on Expressways in the Chicago Region: Recent Trends - 2011 Update

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Regional Bridge Conditions Report (Revised, August, 2011)

Bridge conditions, while improving overall, vary greatly by owner and geography.  This report provides an updated analysis of 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.

Bridge Conditions in the Chicago Region, 2010 (pdf, 5 MB)

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New! Transit On-Time Performance Charts (April, 2011)

As part of the Regional Indicators project, the Congestion Management Process is collecting information on transit on-time performance, among other measures.  Following are charts of some of the on-time data collected.  For more regional indicators, see MetroPulse

CTA On-time Performance, 12-month Moving Averages, 2008-2011

Improvements in CTA on-time performance during 2009 have leveled off.
 

Metra On-time Performance, annual, 2002-2009:

South- and Southwest-Oriented Services
West-Oriented Services

North- and Northwest-Oriented Services

Metra's Electric Service is Metra's highest on-time service, since it does not have any freight interference and the Electric Service power may also be more reliable than other services' diesel locomotives.  On the other hand, the Heritage Corridor suffers from frequent freight interference, and has Metra's worst on-time performance.  The North Central Service, subject to improvement last decade, improved its on-time performance dramatically over the past decade.
 

Amtrak On-Time Performance, 12-month moving averages, 2008-2011:

Short-distance Services
Western-oriented Services

Eastern-oriented Services

Amtrak on-time performance is very sensitive to freight interference.  During the recent recession, when freight volumes and delays were low, Amtrak performance improved.

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New!  Intermodal Freight Connectors: Pavement Condition 2009 Update (January, 2011)

An update of an earlier report on data available in 2006, this report provides a summary of pavements conditions for the National Highway System's intermodal freight connectors.  Intermodal connectors provide access between regional intermodal terminals and the remainder of the National Highway System.  The report demonstrates serious pavement condition issues on the connector highways, but also shows some improvements from the previous report completed with 2006 data.

Intermodal Freight Connectors: Pavement Condition: 2009 Update (pdf, 1.2 MB)
 - Appendix A (pdf, 0.3 MB)
 - Appendix B (pdf, 6.0 MB)

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Speed Limit Compliance on Arterials and Collectors in the Chicago Region, as of 2007.  (December, 2010)

This report explores potential speed limit compliance performance measures for arterial and collector roadways in the seven-county Chicago region. The report includes map exhibits showing geographic distribution of traffic count locations, and summary observations by speed limit class.  Caveats regarding use of the data as a performance measure are included.

Speed Limit Compliance on Arterials and Collectors in the Chicago Region as of 2007 (pdf, 1.7 MB)

Appendices (11.3 MB)

Controlling highway speed is an important strategy to improve highway safety.  Understanding compliance with speed limits is important to undertand the effectiveness of such regulations in controlling highway speed.  One of the potential speed limit compliance performance measures reviewed relates to the 85th percentile speed for a roadway.  We note that John LaPlante, PE, PTOE, stated in his speech accepting the Theodore M. Matson Memorial Award that the 85th percentile speed had been widely misused in setting speed limits (ITE Journal, October, 2010 p. 21).  However, the data posted here (though admittedly problematic) seem to indicate that at lower speed limits, compliance is not high in this region.  However, this should not be seen as endorsing higher highway speeds, but as a recognition that speed limits are not sufficient to control vehicle speed.  Rather, appropriate design is critical.  As Mr LaPlante noted, in planning and designing roads, "our goal should be to select an appropriate target speed for the safety and comfort of all of the road users, as well as the urban context of that road, then design the roadway for that speed.  Once the redesigned road is in operation, we can use the 85th percentile speed to see how well we did and then employ additional speed control measures until we reach our target speed" (ibid.). 

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Trips Underway by Time of Day by Travel Mode and Trip Purpose.  (August, 2010)  

This report uses 2007 Travel Tracker household travel inventory data to compile a picture of weekday travel underway in the Chicago region.  The report contains numerous charts illustrating regional household travel behavior by mode, purpose, and time of day.

Trips Underway by Time of Day by Travel Mode and Trip Purpose for Metropolitan Chicago: Weekday Accumulations of Trips in Motion  (pdf, 1.53 MB)

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Chicago Regional Household Travel Inventory: Mode Choice and Trip Purpose for the 2008 and 1990 Surveys (June, 2010)

This report examines household travel within the northeastern Illinois region and attempts to determine how trip making may have changed since 1990. The main source of data for this analysis is the 2008 Travel Tracker household travel survey which was conducted for the northeastern Illinois region during 2007 and 2008. This survey data was weighted to represent the population of the entire region. The 2008 survey data was compared to the 1990 northeastern Illinois household travel survey, 1990 and 2000 decennial census data, and the 2005-2007 American Community Survey (ACS).

Chicago Regional Household Travel Inventory: Mode Choice and Trip Purpose for the 2008 and 1990 Surveys (pdf, 1.86 MB)

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Highway Ride Quality in the Chicago Region as of 2006 (November, 2009)

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)

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Overview: Why Congestion Management Needs Performance Measurement (June, 2009)

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.

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Previously Published Reports

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.