Network Expansion Decision-making in the Twin Cities

This paper presents a qualitative analysis of the decision-rules used by jurisdictions in Minnesota's Twin Cities metropolitan area. Interviews were conducted with staff at the city, county, metropolitan, and state levels to determine how decisions about road investment, expansion and new construction were made. Flowcharts were developed to provide a more systematic way of presenting that information. Most jurisdictions do not have extensive public participation processes, though several, notably the Metropolitan Council, Hennepin and Ramsey Counties and the City of Minneapolis do. Jurisdictions with public participation have the most formal and extensive documentation of their investment decision process. The decision factors vary by jurisdiction, though safety, capacity, and pavement quality were important throughout.

Forecasting and Evaluating Network Growth

This research assesses the implications of existing trends on future network investment, comparing alternative scenarios concerning budgets and investment rules across a variety of performance measures. The main scenarios compare 'stated decision rules';, processes encoded in flowcharts and weights developed from official documents or by discussion with agency staff, with 'revealed decision rules', weights estimated statistically based on observed historical behavior. This research specifies the processes necessary to run the network forecasting models with various decision rules. Results for different scenarios are presented including adding additional constraints for the transportation network expansion and calibration process details. We find that alternative decision rules make only small differences in overall system performance, though they direct investments to very different locations. However, changes in total budget can make a significant difference to system-wide performance.

Forecasting and Evaluating Network Growth

This research assesses the implications of existing trends on future network investment, comparing alternative scenarios concerning budgets and investment rules. The main scenarios compare stated decision rules, processes encoded in flowcharts and weights developed from official documents or by discussion with agency staff, with revealed decision rules, weights estimated statistically based on observed historical behavior. This research specifies the processes necessary to run the network forecasting models with various decision rules. We find that given the relatively small amount of funds available for network growth in a mature system, alternative decision rules make only small differences in overall system performance, though they direct investments to very different locations and affect the trip time and spatial accessibility in a significantly different way