CATS HOV Bypass Lanes on Metered Expressway

catshovThe 2020 Regional Transportation Plan for the six county northeastern Illinois region (1997) identified the need to investigate the potential for managing traffic operations and increasing vehicle occupancy rates by providing ramp meters with high occupancy vehicle (HOV) bypass lanes on expressway entrance ramps. Three areas are determined as study areas and evaluated by FREQ simulation and microscopic simulation models for a variety of scenarios.

Principal Investigator(s):

Jung-Taek Lee


Jung-Taek Lee
Kazuya Kawamura




The objective of this study is to review and comment on the FREQ simulation model calibration with recommendations for the ramp metering and HOV bypass lanes on entrance ramps at expressways. UIC is also developing the methodology to forecast latent (or induced) demand for traffic in-fill that may result from the implementation of simulation/optimization and the resulting freed up expressway capacity.


FREQ simulation model analyzes study areas for freeway operations with optimization, spatial response, modal response, and all together. Also, these study areas are evaluated under various scenarios: meters only and diversion to arterial, meters with HOV bypass lanes and diversion to arterial, and mode shift to HOV’s. These simulated results will be plugged into a microscopic simulation model such as CORSIM and VISSIM. The microscopic simulation models under a variety of scenarios provide not only more detailed analysis results but also visual presentations to the public. The animated modeling results will be presented on the CATS webpage for the public.

Expected Results or Products:

Expected results include FREQ simulation analysis results (passenger-hours, vehicle miles traveled gas consumption, etc.) under various scenarios. Microscopic simulation results will be presented as well. The analysis of latent demand under various scenarios will be also presented.

NOTE: A report or paper from this research is not immediately available.


Kazuya Kawamura
Urban Transportation Center
University of Illinois at Chicago
412 South Peoria Street, Suite 340
Chicago, IL 60607
Voice: (312) 996-4713
Fax: (312) 413-0006


Chicago Area Transportation Study