I-94 Operational and Safety Needs Study

Oconomowoc to Hudson, Wisconsin

SRF was selected by WisDOT as part of a consultant team to complete the Phase 1 of the I-94 Operational and Safety Needs Study. SRF was responsible for the development of peak hour forecasts for every I-94 mainline segment and ramp along this 280-mile stretch of the interstate for eight horizon years. SRF worked cooperatively with WisDOT staff throughout the forecast development process.

SRF’s work included a review of land use plans, traffic studies and previous traffic forecasts to determine the appropriate growth rates to be used in the development of the peak hour forecasts. SRF balanced the peak forecasts through the corridor by applying an innovative use of CUBE’s matrix estimation program which systematically adjusted 58 interchanges and created origin-destination tables compatible with other traffic simulation software for use in further operational analysis by the study team. Use of other available transportation models was also key to projecting vehicular traffic movement along the study corridor.  These models included:

  • Dane County Regional Model (Madison Area MPO)
  • WisDOT’s Multimodal Statewide Travel Demand Model
  • WisDOT’s Traffic Analysis and Forecasting System (TAFIS) Regression-Based Model

Data from Automatic Traffic Recorders provided detailed historic data on traffic flow within the corridor. WisDOT’s Roadrunner count data also supplemented the hourly ramp usage information.  SRF collected peak period turn movement data on major crossing county trunk highways and arterials in St. Croix County and the Wisconsin Dells interchanges.  Together, the models and traffic counts provided the foundation from which much of the project’s operational, safety and geometric deficiency analyses were built