I-35W North Managed Lanes Study

Twin Cities, Minnesota

The I-35W north corridor is one of a number of major radial freeway corridors connecting greater Minnesota and the growing north suburban area to downtown Minneapolis. As more development occurs in the growing region, traffic volumes have increased where a number of areas in the corridor experience significant congestion each day. The amount of use and congestion is expected to increase by year 2030. In addition, many infrastructure elements are nearing the end of their useful life and need replacement.

Given the daily congestion levels and operational needs of the corridor, MnDOT recognized that leveraging preservation and bridge replacement dollars with safety and mobility dollars could substantially increase benefits to corridor users. Furthermore, MnDOT recently completed the MnPASS System Study – Phase II. This study identified I-35W north corridor, from 3rd/4th Street in downtown Minneapolis to TH 97 in Columbus/Forest Lake area, as a viable candidate for MnPASS lanes and/or a managed corridor. Specifically, the corridor would potentially have increased traveler information and lane controls, increased transit facilities and service, a congestion free choice and HOV advantages.

Under the I-35W North Managed Lanes Study, SRF worked with a large and diverse group of stakeholders, including members from 13 cities, four counties, metropolitan council, metropolitan transit authority, FHWA and MnDOT.  Collaborating with these groups, SRF developed goals and objectives for the study, a public outreach plan, evaluation process and criteria to screen alternatives.

SRF used the Twin Cities Regional Travel Demand Model to produce future traffic forecasts.  Concept alternatives were developed to address specific operational deficiencies along and provide direct access to/from the managed lane to major activity centers and other roadways. The development of these alternatives required creativity as the corridor has limited space for expansion. Concept alternatives ranged from simple auxiliary lanes and buffer lanes to cloverleaf bridge braids and unique flyovers. Based on the project goals and objectives, an evaluation process was used to screen down these concept alternatives to determine the preferred alternative to carry forward into future phases.

This study was all about process as it involved many agencies and evaluated access connections into downtown. Travel demand forecasts and operations modeling were significant components of the effort.