Modeling

CMAP maintains travel models and data resources to support air quality conformity determinations, transportation equity analyses, and planning initiatives.

The Chicago Metropolitan Agency for Planning (CMAP) is responsible for the development and maintenance of travel forecasting methods for northeastern Illinois. These travel demand models predict transportation system use under a variety of socioeconomic conditions and public policy scenarios, and provide information to help decision makers allocate scarce resources. CMAP and its predecessor agency have provided travel demand forecasting for the region since the 1950s.

Trip-based model

CMAP maintains a trip-based model to evaluate long-range regional planning strategies and estimate transportation contributions to regional air quality. This model also helps transportation engineers design construction projects. The main unit of analysis for this type of model is the trip interchange — the journey between two geographic locations representing where a trip begins and ends.

The trip-based model supports the ON TO 2050 long-range plan and its required analysis of air quality conformity. The ON TO 2050 Travel model documentation report describes the overall structure and flow of the models, including how they incorporate My Daily Travel data. A major update to the trip-based model was recently completed, incorporating work-from-home behavior and including additional modes of travel. The 2017 Trip-based travel demand model validation report examines the reasonableness of CMAP’s trip-based model results.

Modeling data is available on the CMAP Data Hub. The trip-based model code is maintained in a GitHub repository.

Activity-based model

CMAP also maintains an activity-based model, which is viewed as a superior method to trip-based models for understanding the socioeconomic determinants of travel choice and evaluating modern transportation solutions. These models are founded on the idea that people’s travel behavior is a result of their daily activities — that the tasks one needs to accomplish during the day dictate where, when, how, and with whom one travels.

The detailed information about people, households, and trips provided by an activity-based model allows for a finer level of analysis than a trip-based model. It also makes them better tools to analyze the effects of policy decisions such as implementing managed lanes, congestion pricing, or alternative transit fare structures.

CMAP recently completed an update to the activity-based model using the newest My Daily Travel survey data and converted the model to the ActivitySim platform. The technical description describes the model structure and required input data.

The activity-based model code is maintained in a GitHub repository.

Freight models

Northeastern Illinois is home to an extensive network of freight facilities and the movement of goods plays a critical role in the local economy, so it is important to understand how freight is transported around the region. CMAP developed a freight forecasting model to help explain the economic choices shippers make when transporting goods. The model documentation describes the overall flow and logic of the model.

To complement the freight model, CMAP developed a commercial services vehicle model to account for the movement of commercial vehicles operating in the region for non-freight hauling purposes. The final commercial vehicles report documents the model design and logic. The freight forecasting model code and commercial services vehicle model code are maintained in GitHub repositories.

CMAP modeling services

CMAP provides modeling data to assist in the development of plans and programs. The agency collaborates on modeling data services with member agencies, universities, and other public agencies; provides ongoing small area traffic forecast assistance to regional partners; and supports the modeling needs of regional partners’ project studies. Contact us for modeling services.

Request traffic projections

For transportation agencies and requestors working on traffic studies for land parcel developments, CMAP can develop small-area traffic projections based on our most recent regional travel demand analysis.

The agency provides traffic projections for 2050. Its travel models use adopted regional 2050 socioeconomic projections and assume implementation of ON TO 2050. Traffic projections consider projects as they appear in the current Transportation Improvement Program and regional transportation plan.

Please send your request to Jose Rodriguez at jrodriguez@cmap.illinois.gov, copy the project sponsor, and include the following information:

Location of the project (including a map or diagram)
Description of existing conditions and proposed improvements
Current volume data: average daily traffic (ADT), average annual daily traffic (AADT), or single day volume count summary at each location for which a projection is requested. CMAP will return 2050 forecast volume in the same data type as it was submitted. After receiving CMAP’s response, you may convert 2050 forecast data to differing volume measure as required or desired
If you need forecast truck volume estimate, please provide a current observed count for each class of truck vehicle available
Description of recent or proposed development that may affect the demand on the facility

Additional instructions for transportation improvement-specific requests: Include a notation (cc) showing that the implementing agency sponsoring the study has received a copy of the request and is aware that it was made (e.g., IDOT, Lake County, municipality, etc.). The sponsor will receive CMAP’s response, and you will receive a copy.

Additional instructions for parcel-based development consultants preparing traffic impact studies (right-of-way access permits, growth rate, HUD noise analysis): Follow the same instructions listed above for transportation improvement requests. In addition, include a basic designation for the type of parcel development (commercial, residential, industrial/logistic, educational/institutional, or mixed use, specified with the use types), plus any additional information about the development (number of buildings on site, square footage/gross floor area, number dwelling units, access/egress locations) the requestor and client have agreed to share with CMAP. Note that the provision of traffic projection data does not constitute a CMAP endorsement of the proposed parcel development or any subsequent parcel developments.

As CMAP develops small-area traffic projections for implementing agencies, we will also check whether the location in question is on the Strategic Regional Arterial system and will direct you to review the relevant report for accompanying recommendations.