I-495/I-90 Interchange Project
Massachusetts Department of Transportation
The interchange at I-495 and I-90 is considered the crossroads of Massachusetts, carrying half of all freight traffic, and approximately 75,000 vehicles per day travel through the interchange. HSH is part of the team providing traffic and transportation engineering, and community engagement services for this project to provide a safe and efficient interchange for the 21st century. With regional and statewide interests pertaining to this interchange, the community process has been designed to balance institutional input in addition to environmental and constructability limitations. HSH also led the traffic analysis for this complex project. The work involved extensive Vissim traffic modeling of alternatives to evaluate operations and user costs associated with delay. Additionally, HSH led a robust safety analysis effort to compare the safety of each alternative using the Interactive Highway Safety Design Model (IHSDM) Crash Prediction Module (CPM). The IHSDM is a software analysis program which evaluates the safety and operational effects of geometric design decisions on highways.