By definition, integrated corridor management involves coordinating various component parts of a corridor so they work together harmoniously. These parts (freeways, arterials, transit, etc.) are identified and managed by sending and receiving data about them.
Basic data flow
At its most basic, the data flow for an ICM system looks like this:
Traffic sensors and data feeds provide data to the corridor management systems and the people who operate them. With the help of a Decision Support System (DSS), a decision about how to manage a traffic situation on the corridor is made and implemented.
However, when we add the stakeholders who contribute to the input and receive the output, it becomes evident that the process is more complex:
Communication and data standardization
Stakeholders in multiple jurisdictions and data from multiple traffic management systems must communicate with each other, pointing to the need for standardized interfaces and data communication protocols across the entire system:
Types of data, controllers, communication channels
Adding the types of stakeholder data entering the system and the controllers and communication channels needed to carry out any changes reveals the range of information that must flow through the system:
Corridor management and decision support
The strands of data intersect in the central subsystems of Corridor Management and Decision Support:
- Corridor Management. Corridor Management focuses on detection and management of corridor incidents and performance. For an ICM system in California, that means linking data from Caltrans' Advanced Traffic Management System (ATMS)—including freeway ramp metering control, freeway changeable message signs (CMS), and arterial signal control at ramp intersections—with city/county arterial signal control and CMS, along with metrics to gauge system performance. It is the effective interrelationship and communication among these components, as well as the collaborative interactions among the agencies that operate them, that make coordinated corridor-wide operations possible.
- Decision Support. Decision Support helps corridor managers decide how to respond to traffic events. It provides a set of response options (a "playbook") and uses modeling and simulation to forecast "what-if" scenarios under various conditions, so system operators can visualize and evaluate the effect of choosing one strategy or another.
Integrating the components
The relationship of these components is illustrated in the following diagram:
Freeway-arterial system integration
- Integrating freeway and arterial operations requires coordination and communication between Caltrans' Transportation Management Center (TMC) and other TMCs operated by cities and counties along the corridor.
- That means the data from those systems needs to be transmitted back and forth between them either directly or through some infrastructure that handles the input/output data processing (such as an Information Exchange Network, or IEN).
- This example, using information from the I-210 Pilot, shows that the city and county TMCs use a variety of traffic management systems, an important consideration for sharing data.
- The Decision Support System, hosted in the Caltrans TMC in this example, is part of this comprehensive data sharing, since the DSS needs to assess conditions and simulate possible responses based on that data.
- Interfaces between all the components are also required, so all system operators see the same things.
Transit and parking
Transit data (bus and rail stations, arrival/departure times) and parking management information (total spaces, available spaces, parking reservations, pricing) need to be added to the data flow and visible to system operators.
Traffic conditions, corridor changes, transit service schedules, and parking information need to be communicated to the traveling public. In addition to freeway or arterial CMS, options could include:
- 511 services
- Dedicated corridor website
- Mobile device app
- Social networking
- Radio advisories