Experience from the Integrated Corridor Traffic Management Project in Minnesota
To address the growing congestion levels in the Twin Cities area, the Minnesota Department of Transportation (Mn/DOT), in partnership with Hennepin County and the cities of Bloomington, Richfield and Edina, launched the integrated corridor traffic management (ICTM) project as a field operational test (FOT) in 1994. The purpose of the ICTM project was to increase corridor capacity along an 8-mile section of the Interstate-494 south of the Twin Cities by installing an integrated system of adaptive ramp metering, adaptive traffic signals, and motorist information and surveillance systems. The conclusion from the evaluation report was that the ICTM project produced improvements to traffic operations and the use of capacity. One of the most important outcomes was the emergence of a strong, cross-jurisdictional partnership that continued collaborating to improve corridor operations, even after the completion of the ICTM project.
The Integrated Corridor Traffic Management (ICTM) project was a complex endeavor consisting of technical and organizational challenges. The project aimed to mitigate the increasing congestion produced by the rapid growth and increasingly high levels of congestion in the Twin Cities area. The project deployed control and communications systems along an 8-mile corridor that spanned five jurisdictions. Thus, the project required multiple agencies, which until the start of the ICTM project in 1994 worked independently from each other, to coordinate in the planning, funding, deploying and operating of cutting-edge technical systems deployed over an 8-mile corridor that encompassed I-494, four parallel arterial streets and seven perpendicular arterial streets. A partnership consisting of public agencies (the Mn/DOT, FHWA, and agencies from the cities of Bloomington, Richfield, and Edina and the county of Hennepin) and private vendors guided the planning, deployment and operations of the ICTM from its start in 1994 to its full deployment in 2000.
The purpose of the ICTM technologies was to balance traffic flow and capacity at the corridor level through the adaptive control of traffic signals and ramps, and to improve incident management strategies through a motorist information system. Deployed systems included an adaptive traffic control system for arterial traffic signals and freeway metered ramps, a queue detection system to prevent queue spillover from the metered ramps onto the adjacent streets, an incident management system including 11 arterial closed-circuit television (CCTV) cameras, and a motorist information system including trailblazing and dynamic message signs for the purpose of diverting local and regional traffic.
In addition to estimating the benefits of the deployment, the evaluators identified lessons learned on the ICTM strategy of deployment and contracting, which include the following.
- Consider a modular approach to deployment in which the deployment proceeds in separate sections. The project was deployed in four modules across a 5-year span. The complexity of the project in combination with the shortened construction season in Minnesota warranted deploying the project in four modules in 5 years, from 1994 to 2000. Following the modular approach to deployment had a couple of key advantages. First, each module had a set of manageable goals that enabled a concentrated work effort for achieving specific outcomes. Second, it allowed project staff to learn how to operate the new systems incrementally, and for project managers to apply lessons learned from prior module deployments to subsequent ones.
- Beware that there are risks, in addition to advantages, associated with a modular deployment. The experience of the ICTM project showed that using a modular approach extended the deployment schedule, which led to stakeholders losing interest in the project over time (when other projects and issues arose that demanded their attention). In addition, the longer deployment period increased the difficulties and costs of the evaluation. For example, during the ICTM deployment period from 1994 to 2000, other improvements and changes occurred along the corridor, such as the construction of new streets and housing complexes, replaced traffic signals, and increases in traffic volume, all of which reduced the capability of reaching firm conclusions about the effects of the ICTM. Lastly, an extended deployment schedule increases the risk of funding interruptions and delays (which happened in the ICTM project).
- Consider the option of using different contract mechanisms for subsystems in a complex project. Complex projects often use the design-build and/or the design-bid-build type of contracts. In a design-build contract, the transportation agency uses the services of one entity (e.g., a consulting firm or in-house staff) for the design and construction of a system. The agency invites contractors to submit bids and then manages the contractors. In contrast, in the design-bid-build mechanism, the transportation agency contracts with separate entities to do work on different elements of a project. To deliver the various components of the ICTM, the ICTM management successfully used both design-bid-build and design-build procurement mechanisms. Although the project primarily used a design-bid-build mechanism, it employed a design-build mechanism for the motorist information system. A design-build strategy was appropriate for the motorist information system because it was not commercially available as an off-the-shelf product, and it required a comprehensive development of features and functions unique to the ICTM.
To manage the deployment of a complex project in a region with a shortened construction season, the ICTM project followed a modular approach. The approach also had the benefit of allowing management the opportunity to apply lessons learned during the deployment of one module to the next. The ICTM also employed both design-bid-build and design-build contract vehicles, depending on the needs of the particular subsystem. These deployment strategies, which enabled the ICTM partnership to complete the ICTM project, are worthy of consideration by transportation agencies that are preparing for or managing complex transportation improvement projects.