Integrated Corridor Management (ICM) Program: Major Achievements, Key Findings, and Outlook

Appendix B. Questions Agencies May Have About ICM

This section provides a listing of frequently asked questions about ICM along with answers and explanations where possible.

• Is my region conducting ICM or some other corridor or freeway management practice?
  • Because ICM is a response-triggered strategy, it does not replace management of construction projects or day-to-day operation to maintain a highway or even a system, in the sense that nominal recurring delays, fender benders, highway service patrols, occasional rain, ramp metering, HOV hours and restrictions, et al, already exist. Rather, the USDOT’s informal definition of ICM is not merely a one-off local-incident traffic detour, or even a traffic incident management (TIM) program or plan, or a pre-planned construction or special event mitigation plan with a detour(s), but a real-time multi-agency collaboration "response to a severe sudden and non-conforming event" that necessitates concurrent cross-agency response to that atypically forming incident. It invokes several layers of route and/or mode management and pertains to major atypical events that would otherwise, and suddenly, cause hours of delay or be newsworthy in their random severity. ICM is "event driven" in real time, as exhibited by the San Diego and Dallas experiences that only a few candidate ICM events were triggered each week. It is neither a months long construction mitigation plan, nor is it a special event plan, nor a routine TIM response. ICM requires the pre-agreed support of as many adjacent and complementary agencies as possible, with their resources, in the guise of state, county, and local street systems, signal departments, transit and commuter programs and resources, media and ITS-related partners all working together. There are myriad other non-ICM highway and freeway management practices that are practiced more or less solely on the "trunk" facility, like ramp metering, HOV lanes, ATDM, speed harmonization, part time shoulder use, standard highway service patrols, and highway lane-and queue-attention, et al, that by and of themselves, do not constitute ICM. For example, a simple detour off the trunk highway, through side streets, and back onto the highway, is not ICM in the purest sense, unless remediation is promoted to the entire region, in real time messaging, with transit incorporation, and multi-agency involvement. ICM employs route- and mode-alternative diversions, including reformatting the openings, closings, timings, and messages of those diversions during the impacting event, and then returning them to nominal operation once the event has subsided.
• Is a Decision Support System (DSS) necessary to achieve integrated corridor management? Can I deploy an ICMS without a DSS?
  • Although transportation management decisions are always necessary to manage a corridor effectively, you do not necessarily need a DSS to achieve integrated corridor management. Particularly in less complex corridors with fewer traveler options, TMC operators may be able to handle the decision-making needed to implement basic ICM strategies. However, for a complex corridor with lots of modal options and diverse traffic conditions, you should consider the benefits and costs of a DSS to assist with managing your corridor as a network. Implementing a DSS is a large undertaking and should not be taken lightly. You may want to start with a more basic system that has various tools to show transportation operators what the traffic conditions are or are predicted to be in the near future and build from there. Ultimately, some level of DSS automation is usually necessary to reduce the workload on TMC operators.
• What benefits can I expect from ICM without a DSS?
  • Every situation is different, but without a DSS, you will be relying on human operators and operations staff to communicate with operators from the other agencies and make coordinated decisions regarding control and information strategies that may be required under incident, construction, high demand, or special event conditions in the corridor. Benefits are expected to be greater where disciplined pre-planning has been performed to identify alternate routes, signal changes, and possibly modal shifts to accommodate the corridor traffic as much as possible. Network operators should go through the ICM process to develop consensus incident response plans for the response "playbook". This process helps operators better understand other network operations and the impacts that these systems can have on the corridor. Ideally, the operations agencies in your corridor will have a frequently updated "common operating picture" of the conditions in the corridor, so that they can act according to the same information.
• If ICM is only for major crashes, and extremely high demand/congestion, or emergencies, then are there any benefits for more routine incidents and day to day variability?
  • To some extent, the answer to the question depends on the concept of operations you and your stakeholders have for managing your corridor, as well as network and transportation characteristics, such as resiliency and overall level of congestion. If you decide to set a performance or disruption threshold that is high prior to implementing various response strategies, then you will not invoke the strategies as often as you would with a lower performance threshold (as shown by San Diego).
  • One of the proven benefits of ICM is that there is an increased awareness of even nominal incidents in the corridor as well as visibility into daily traffic conditions. This situational awareness assists in managing day to day variations and routine incidents, but strictly speaking, ICM only invokes for the worst of the worst events.
• Can I deploy an ICMS incrementally?
  • Yes, absolutely. In fact, building your ICM capabilities incrementally is likely a given with limited budgets and competition of various projects in your region for funding. The Dallas and San Diego sites implemented an ICMS in a relatively short amount of time; however, they were specifically funded by USDOT to do so. Incremental deployment will also provide more time to advance your DSS capabilities in a gradual fashion.
• If ICM is so beneficial, why did the Dallas stakeholders stop using the ICM DSS?
  • Collectively, Dallas stakeholders are still supportive of the ICM program and use many of the capabilities brought to the region with the demonstration program. However, the DSS implementation in Dallas had several limitations, including the need for multiple layers of human intervention before a response plan could be implemented. Additionally, several infrastructure changes and major new roads within the corridor network during the demonstration period resulted in a need to update the predictive data model. Since no stakeholder stepped forward to lead and fund the effort that would be needed to update the model, Dallas stakeholders decided it was in their best interest to discontinue use of the DSS for real-time operations. Also, during the ICM test phase, the Dallas network operators learned a great deal about the types of response plans that were most effective in their corridor and felt less reliant on the predictive data model.
• Is an overall ICM champion still needed?
  • It never hurts to have an articulate and politically savvy champion for ICM within your region, but perhaps it is more important to have individual agency proponents for the key ICM stakeholders associated with the corridor you want to manage. Initially, in Dallas, DART was the champion agency (and ICM host) but over time that duty transferred to TXDOT. In other locations the city, MPO, or regional authority may be the champion, and not always the DOT. ICM represents a different mindset as compared to traditional network operations, so it helps in the early stages to have many champions to make the case for change. Gradually, as ICM becomes more accepted as a standard practice, the need for champions will lessen. To mainstream ICM into the transportation planning and programming processes, the leadership of each stakeholder organization must be supportive of ICM and understand what it means to their agency. Given the realities of staff turnover and attrition, there is a need within each agency to have multiple personnel knowledgeable and supportive of ICM, at various job levels and spanning planning, operations, and project management responsibilities.
• Why is it that the benefit-to-cost ratios projected from the evaluation of the demonstration sites were not higher?
  • The final evaluation report for the ICM demonstrations showed a range of benefit-to-cost ratios for San Diego from 2:1 to 9:1 and Dallas from 0.55:1 to 1.64:1. See the evaluation final report for more information. The ranges were based on varying assumptions for activations over a 20-year horizon and relied heavily on simulation modeling work that was done for the post deployment AMS activity, which relied on a static weighting of incident types and frequencies. Only the incidents in the AM or PM peak were considered in the analysis. The B-C ratios would be higher if all incidents, including those outside the peak periods, were considered. The ratios would be even higher if the overall frequency of incidents increased over the 20-year horizon. The weighting and characteristics of various incident types, based on cluster analyses, would not remain fixed over 20 years and would have to be recalibrated from time to time to improve the accuracy of the analysis.
  • Because of methodological difficulties, the evaluators did not try to monetize other realized benefits such as traveler or operator satisfaction, improved situational awareness, improved agency collaboration, and other institutional benefits. In addition, individual network benefits that may be attributed to ICM enhancements were excluded from the analysis. Therefore, the benefit-to-cost ratios under-represent the true benefits of the ICM demonstrations.
• What advances have been made since the time the ICM systems of Dallas and San Diego were designed and implemented that current deployers can take advantage of?
  • Advances include more research on and experience with DSSs, improved simulation modeling capabilities, the availability of a rich set of new ICM strategies that can be leveraged from connected and cooperative vehicles and shared use mobility concepts such as MOD¹⁴. In addition, more consultants have experience with ICM planning and implementation than were available at the time the systems of Dallas and San Diego were being designed. Beyond that, the availability of third-party data on network traffic conditions made available from Crowdsourced applications such as WAZE, INRIX, or HERE has grown substantially in the last few years. These applications enable arterial network coverage to be much more robust than in the past.
• Why should we implement ICM in our region? How will I know when we are ready to begin?
  • FHWA has a flyer entitled "10 Attributes of a Successful ICM Corridor"¹⁵ that suggests when a region is candidate for ICM.
  • Working in collaboration with other agencies, integrated corridor management promotes a change towards proactively managing corridor traffic considering the traveler first, instead of agency systems or jurisdictional boundaries. The San Diego and Dallas ICM deployments demonstrated the benefits of this approach.
  • Discussing the concept of integrated corridor management and potential strategies with other stakeholders can begin right away, while serious project planning and deployment of ICM systems in your corridor should wait until you have visibility into operational status and conditions of each important network within the corridor. In addition, corridors with current or predicted congested conditions and variability in traffic conditions plus viable alternative modes and routes to the freeway are better candidates for integrated corridor management.
• Where should I go for help?
  • Many ICM initiative deliverables were produced during the program that may serve as a reference or example for others interested in deploying the concept. A great place to start would be to search the FHWA Office of Operations website and/or the Joint Program Office of ICM knowledgebase. In addition, USDOT plans to provide ongoing KTT support through facilitated workshops and other targeted assistance.
  • For more information contact the ICM Program Manager in the FHWA Office of Operations or the USDOT Intelligent Transportation Systems Joint Program Office website: keyword, ICM or related.