Building Our Way Out of Congestion - Highway Capacity for the Twin Cities

Gary Davis, Civil Engineering
Kate Sanderson, URS Corporation

October 8, 2003

What would it take to build our way out of congestion? To answer this, a minimal set of highway capacity expansions that accommodates future travel demand and guarantees mobility must be determined. The problem of identifying capacity expansions that are in some sense optimal, while accounting for traveler reaction, is known as a network design problem. Numerous formulations and solution algorithms have been published over the last three decades, however the problem of implementing these for large-scale networks has remained a challenge.

This research presents a solution procedure which incorporates the capacity expansion as a modified step in the Method of Successive Averages. This provides an algorithm capable of solving problems of real-world complexity. A network design problem is then solved for the freeway system of the Twin Cities, providing a lower bound on the extent to which physical expansion of highway capacity could be used to accommodate future growth while guaranteeing a given level of mobility.

Mechanistic– Empirical 2002 Guide for Design of Minnesota Low-Volume Roads: The Future of Pavement Design is Here!
(Almost Here)

Lev Khazanovich, Civil Engineering

November 12, 2003

This presentation provided a brief overview of the 2002 Design Guide, a mechanistic-based design procedure developed under the National Cooperative Highway Research Program (NCHRP) 1-37A study and sponsored by AASHTO. The Design Guide represents a major change in the way pavement design is performed.

The mechanistic-empirical format of the Design Guide provides a framework for continuous improvement to keep up with changes in trucking, materials, construction, design concepts, and computers. In addition, guidelines for implementation and staff training to facilitate use of the new design procedure, as well as strategies to maximize acceptance by the transportation community are included.

A recently initiated study, sponsored by the Minnesota Department of Transportation and the Minnesota Local Road Research Board, will adopt this procedure for design of low-volume Portland cement concrete (PCC) roads for Minnesota conditions. A catalog of recommended design features for typical site conditions (location and traffic) will be developed using 2002 design software with recalibrated models.