The Institute of Transportation Studies distributes FREQ12 a Windows version of their long existing Freeway Corridor Simulation Model (pdf).

Availability: FREQ12 can be ordered from the ITS Systems Unit.

Training: Educational programs continue to be offered periodically for both the public and private sectors. Send email to lannon@berkeley.edu to be put on mailing list for future Workshops.

Background: During the past thirty years, the Institute of Transportation Studies at the University of California at Berkeley has developed and applied a sequence of freeway simulation models for the evaluation of various design and operational improvements. These models have been used by researchers and professionals both in the United States and abroad. Interactions with model users and experience in educational programs have led to continuous improvements in these models.

Description of model: The FREQ12 system of models includes an interactive graphical interface with comprehensive input checking, carefully selected default values, on-screen graphic representation of the simulation results, and user-selected output options including traffic performance contour maps. The two models contained within the FREQ12 system are: FREQ12PE, an entry control macroscopic model for analyzing ramp metering; and FREQ12PL, an on freeway priority macroscopic model for analyzing HOV facilities. The FREQ system of models has received extensive testing over many years and has been applied to freeway corridors in numerous urban areas throughout the United States and abroad. The latest version of FREQ, FREQ12, is currently being used in nine Districts as part of a CALTRANS freeway operations training program.

Sample output and more details can be viewed in the FREQ12 release announcement (pdf)

Type of analysis: The FREQ system of models enables the user to analyze geometric design improvements, an on-freeway HOV facility, normal and priority entry control, or time-varying capacity reduction situations such as reconstruction activities or freeway incidents. The analysis emphasizes traffic simulation, traveler responses, and measures of effectiveness.

Description of Corridor that can be analyzed: FREQ can analyze a one-directional freeway corridor that can include an arterial or group of "bundled" arterials. The current version of the model, FREQ12, can analyze approximately 50-100 miles of freeway corridor with a maximum of 158 subsections,78 origins and 78 destinations.

Recent enhancements: FREQ12 has been rewritten as a Windows application with added features to simplify data entry. The FREQ12 integrated system of models includes speed-flow relations that are included in the 2000 Highway Capacity Manual. On-screen color graphic displays of the analysis are included in the output options. The latest version of FREQ12 can analyze an on-freeway HOV facility in combination with ramp metering (some restrictions).

History of modifications: A complete history of the FREQ12 enhancements and bug fixes can be viewed/downloaded (pdf)

System requirements: FREQ12 requires a PC computer with the Windows operating system and a hard disk with 5-10 Mbytes of free disk space. FREQ12 is a Windows application that runs under Windows 98, NT, 2000, and XP.

Contact Information: For more information about FREQ, please contact Lannon Leiman at the ITS Systems Unit:

To order: FREQ12 can be ordered from the ITS Systems Unit
_