CMAP has completed a comprehensive travel and activity survey for northeastern IL*. Data collection took place between January 2007 and February 2008. A total of 10,552 households participated in either a 1-day or 2-day survey, providing a detailed travel inventory for each member of their household on the assigned travel day(s). The resulting distribution of the sampled population closely matches northeastern IL's household population by county. The public use data set is now available for download below. (1990 data are also available below for comparison and trend analyses)
* An identical survey was done for the three-county northwestern Indiana region. For information related to Travel Tracker data for NW Indiana, please contact the Northwestern Indiana Regional Planning Commission (NIRPC).
Data and Documentation
Click the link below to download the Travel Tracker public data set in MSAccess format. Note that there are six main tables in the database, as described in the following table. In addition, when interpreting the data, be aware that households are divided into five distinct strata, ranging from areas that have minimal access to transit and low population density, to areas that have maximum access to transit and high population density. For details about the data format, sample stratification and other related issues, please see the Data Dictionary and User's Guide. For methodological issues, refer to the Pilot Study Report.
Pilot Report and Original Design
Data Summaries and Analyses
Below are weighted and unweighted versions of some basic tabulations drawn from the Travel Tracker Survey data set. The tabulations Include detailed tables at the county level showing the distribution of trip purposes, trip modes, travel times, and more, The weighted data are calculated using the sample weights that are included with the original data set. For information about these weights, please see the documentation available for download above.
Below are several examples of animated sample travel days illustrating anonymized travel logs taken from the Travel Tracker Survey data. The auto mode example comes from GPS devices that respondents' carried in their vehicles, while the mixed-mode examples come from wearable GPS units. To view, download the files and unzip. Use Windows MediaPlayer or a compatable program to run the animation. Note the clock in the upper left to follow travel times.
Should I use the Weighted or Unweighted Data?
The weights included with the data set were derived by comparing the sample data's demographics to actual population demographics by county. Factors included in the weighting calculation are race/ethnicity, household size, household income, and age of householder. While weights are designed to correct for under-representation and over-representation of certain sub-populations in the sampled data, they should be used with caution. For example, if a household with a very unusual travel characteristic (e.g., bicycles 25 miles round trip to work) happens to have a very large weight (because they represent an under-represented demographic in the sample), the weighting process amplifies their unusual travel behavior to the entire data set. Looking at the travel patterns of households with high weights might be a good place to start when using the weighted data set, therefore. If problematic households are identified, one might decide to drop those households from the data and re-weight the data set. Note the distribution of the weights below. Here are some households that some analysts might consider for removal or re-weighting, depending on the nature of the analysis.
Click here to download the ENTIRE 1990 Travel Survey data set in all three formats (MSAccess, SAS, and Text), including documentation . To download the data in only one format, please use the links below.
For questions or comments about the 1990 or 2000 Travel Surveys, email traveltracker@cmap.illinois.gov.