An Iowa DOT assessment of potential ICM strategies.
This Integrated Corridor Management (ICM) project focuses on developing operational strategies that will enhance safety, mobility, and travel time reliability for travelers in the Des Moines Metropolitan Area. The primary goals for this project are as follows: reduce fatalities and injuries, reduce travel time, improve traveler mobility, improve road and system efficiency, integrate multimodal transportation systems, improve accessibility, improve regional economic vitality, and maintain regional transportation systems. The ICM Project began in October 2018; the first phase identified ICM strategies that addressed current needs while the second phase developed a timeframe for implementing a hybrid bundle with associated strategies and evaluated medium to long-term strategies in terms of implementation ease, ICM benefits, and sequential order to determine relative timing (mid-range or long-range). The project is bounded by U.S. Highways I-235, I-80, I-35, Iowa 163, and any additional highways and arterials connecting to these freeways. The analysis utilized multiple predictive tools to evaluate competing packages of ICM improvement and conducted comparisons between different strategies based on the performance measures.
Five bundling strategy concepts were developed to organize individual strategies by primary intention and functional area. The bundling concepts are as follows: aggressive freeway build, intensive transportation management, transit and travel demand management, balanced, and targeted transportation management. Since Balanced and Intensive Transportation Management strategies had the highest overall improvement across safety, mobility, reliability, integration and connectivity, accessibility, and systems management, a hybrid bundle that balanced agency priorities with strategy performance and bundle costs was developed. The Intensive Transportation Management bundle forms the basis of the hybrid bundle with modifications made based on the preferred strategy implementation packages.
Hybrid bundle costs were developed based on previous project cost estimates and sources (including the Federal Highway Administration and consultant estimates). Equipment replacement costs were based on assumed equipment/infrastructure life cycle then converted to an annual amount. Capital and operational costs were estimated using the estimates of individual strategy costs. Planning-level costs of hybrid bundle are estimated. The total capital cost for the hybrid bundle was estimated at $452,165,000. The annual operating cost was estimated at $1,771,500 and the annual maintenance cost was estimated at $11,917,500.
Cost estimates of the strategies included in the hybrid bundle are summarized below.
- Traffic management center enhancements (including the addition of active freeway management systems) had an estimated capital cost of $320,000 and an estimated annual operating cost of $225,000.
- Ramp metering, assuming there were 61 ramps total and each ramp costs $145,000 to construct, incurred an estimated capital cost of $8,845,000; the annual operating cost was estimated at $368,000 and the annual maintenance cost was estimated at $305,000.
- Dynamic shoulder and junction control would be applied to a roadway 28 miles long (with construction costing $3,000,000 per mile). The total capital cost was estimated to be $84,000,000. The annual operating cost was about $59,500 and the annual maintenance cost was about $2,240,000.
- A dynamic queue warning and speed advisory system--assuming it cost$500,000 to construct a system at a total of 62 locations—an estimated capital cost is $32,000,000 was incurred.. The annual operating cost was about $119,000 and the annual maintenance cost was about $560,000.
- A traffic signal management system had an estimated cost of $3,000 per year for each of 800 signals; the estimated total capital cost was $72,000,000.
- Adaptive signal control signals had an estimated construction cost of $50,000 each. A total of 800 signals were estimated to incur a capital cost is $40,000,000 and the annual maintenance cost of about $3,200,000.
- Freeway bottleneck improvement or elimination projects had a projected implementation of about $500,000 each. The capital cost for 250 of these projects was about $125,000,000 and the annual maintenance cost was about $3,750,000.
- Arterial roadway improvement projects had estimated costs for implementation on75 miles of roadway. Assuming an incremental cost of $1,000,000 per mile, the total capital cost was about $75,000,000 and the annual maintenance cost was about $1,562,500.
- Establishing a transportation management association was estimated to cost about $200,000 annually to operate.
- A bike share system with a 300-bicycle initial deployment was estimated to incur a capital cost of $2,400,000 and an estimated annual operating cost of $600,000.
- Transit signal priority systems constructed at 100 intersections at about $6,000 each had a capital cost of about $600,000 and the annual operating cost of about $200,000.
- Transit lanes at 15 intersections (assuming each cost about $800,000 to construct) were estimated to result in a capital cost of $12,000,000 and an annual maintenance cost of about $300,000.
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