The I-70/I-71 corridor in downtown Columbus, Ohio, is one of the busiest and most vital sections of highway in the region. It serves approximately 150,000 vehicles and 17,000 trucks per day. Although it makes up only three percent of the I-70 and I-71 freeway system in Franklin County, it accounts for 21 percent of all I-70 and I-71 crashes. As a result, the Ohio Department of Transportation (ODOT) identified the corridor for a major transportation improvement project.
For both the strategic planning and preliminary engineering phases of this project, B&N was responsible for traffic forecasts and traffic operational analysis of the freeway and connected local street system for this highly complex and developed urban corridor. As a subconsultant to ms consultants, B&N performed these services for one of the largest ongoing freeway reconstruction projects in the United States ($1.8 billion). The traffic forecasts and analysis included 20 freeway interchanges and 60 intersections within the corridor.
Traffic Modeling Strategic Planning
In the project’s strategic planning phase, B&N created one of the largest microsimulation models ever developed that could dynamically assign traffic to the system based on changes in the roadway network. This allowed for accurate and efficient reassignment of traffic volumes as numerous alternatives were evaluated for the project. Then, based on the traffic assignments, B&N prepared traffic analyses used in selecting the preferred improvements.
Traffic Forecasts
For the preliminary engineering phase of the project, B&N developed ODOT-approved Certified Design Traffic (design year traffic forecasts) for the preferred alternative, based on travel demand model assignments from the Mid-Ohio Regional Planning Commission (MORPC). The travel demand model assignments were refined by B&N through the application of National Cooperative Highway Research Program (NCHRP) Report 255 volume adjustment methodologies. This process to refine future year traffic assignments, led by B&N, resulted in a logical and defensible set of traffic forecasts that could be used in obtaining project approvals from ODOT and the Federal Highway Administration (FHWA).
Interchange Modification Study
B&N also was responsible for all the analysis and report preparation for the Interchange Modification Study (IMS) that was approved by the FHWA.
Portions of the overall project are underway, in various phases of design, construction, or completion.