The Minnesota Department of Transportation in partnership with local agencies launched the integrated corridor transportation management (ICTM) project in 1994 to improve capacity and operations along an 8-mile corridor south of the Twin Cities. The ICTM project deployed advanced technology and employed an integrated management approach to corridor management. Project technologies included control systems for adaptive ramp metering, adaptive arterial traffic signals, a motorist information system using dynamic signage to direct traffic during incidents and surveillance systems. The evaluation of the project gathered quantitative and qualitative data from field observations, automated databases, and ICTM system users, and identified several benefits in corridor traffic operations and management. Drawing clear "before/after" conclusions on the outcomes of the ICTM was difficult due to the myriad of changes that had occurred along the corridor during the 5-year period of deployment (such as a rapid growth in population and housing, road expansion and building, etc.). Nonetheless, the evaluation report outlined key system impacts and lessons learned.
The Integrated Corridor Traffic Management (ICTM) project deployed a set of technologies to improve capacity and operations along a corridor that included I-494, four parallel arterial streets and seven perpendicular arterial streets. The rationale for the project was the increasing volumes of traffic and anticipated growth in the Twin Cities, MN area. Determining system impacts of the ICTM was challenging because many other significant changes took place during the 5-year deployment. Nonetheless, survey data from 400 area motorists, and interviews with agency representatives and stakeholders indicated that the deployment improved the corridor's capacity and helped to balance network traffic loads on arterials and freeways. Specific findings include the following.
The ICTM improved capacity on the parallel arterial streets through adaptive control signals.
- 58% (232) of the motorists surveyed indicated that they were less likely to use I-494 for short trips. Prior to the ICTM, I-494 was used heavily for short trips, contributing to congestion levels. Ease of use and freeway / ramp metering congestion were cited as the primary causal factors by motorists for increasing the use of side streets for short trips.
- 49.8% (163) of motorists surveyed revealed that they used corridor side streets more often than they had prior to the deployment for short trips; 44% (144) and 4.6% (15) indicated that they used side streets about the same or less often than a year ago for short trips.
- Out of the 30 agency stakeholders surveyed , 58% perceived that traffic operations improvements within the corridor had contributed to local trips using local streets rather than I-494 freeway, and 50% of the stakeholders perceived that the application of adaptive control systems had optimized the use of corridor capacity during non-incident conditions.
The ICTM improved traffic operations within the corridor during non-incident conditions.
- Measures of Effectiveness (MOEs) of traffic operations improved along most corridor routes, as measured by volume-adjusted MOEs but mostly remained the same when measured against unadjusted MOEs.
- Traffic operations MOEs improved on north-south streets, considering the increased traffic demand.
- Traffic operations worsened in general on several streets during the morning peak hour.
Despite the improvements to capacity realized through the ICTM, motorists perceived traffic operations within the corridor to have worsened, especially along I-494 and the metered ramps. This finding is not inconsistent with the increases in population growth, development and number of vehicles in the area that occurred during the 5-year ICTM deployment period. Thus, although the ICTM deployment improved the capacity of the 8-mile corridor to adapt to increased demand, the demand continued to grow and place heavy demands on the corridor.