The management of multi-jurisdiction, multi-modal corridors for the efficient transportation of people and goods presents a unique set of technical, procedural, and organizational challenges. The intent of this project is to coordinate the various transportation networks and control systems in use within the I-210 corridor to enable them to operate as a cohesive and integrated system. To do so, the project team, in collaboration with project stakeholders, will investigate tools and technologies and develop processes that will help Caltrans and corridor partner agencies enhance their real-time collaborative decision-making capabilities.
Key user-related issues to be addressed by the project include:
- Management of congestion spanning freeway and arterials
- Coordination of transit and roadway operations
- Enhancement of situational and operational awareness
- Development of coordinated strategy management
- Enhancement of communication with system users
- Management and monitoring of deployed system
Traffic congestion across the I-210 freeway and surrounding arterials is the primary problem to be addressed. Congestion occurs when demand for travel along a roadway segment exceeds the capacity of the existing infrastructure. Congestion can happen:
- On a recurring basis, such as during every peak travel period on weekdays
- During anticipated events, such as the Rose Bowl or other special events of significance
- Unexpectedly, because of unplanned events that reduce roadway capacity such as traffic accidents, wildfires, or other occurrences
While many transportation system operators already dedicate significant efforts to addressing the congestion that affects their transportation systems, these efforts often remain confined to their specific network. For instance, Caltrans typically tries to resolve congestion issues along freeways, while cities along the I-210 corridor typically focus only on what happens on surface streets. However, congestion often spreads across networks. Congestion on the freeway often spreads onto local streets; on local street networks, congestion also often spreads across jurisdictional boundaries.
The problem of addressing congestion has multiple facets. First, it is necessary to identify the extent and possible cause of the problem by evaluating the performance of individual field elements. This evaluation must also take into consideration planned and unplanned events that may influence system operations. Once operational issues have been identified, actions may be taken to adjust the capacity of roadway elements and influence, to the extent possible, travel demand within the corridor to maximize system performance. The actions to be taken will depend on any previously identified and approved response strategies, as well as on the ability to activate the related control devices.
While local transit operators have already devoted significant efforts to providing efficient transit services to the I-210 corridor, further improvements could be achieved by coordinating transit and roadway operations. For instance, transit agencies could alter bus routes or offer additional rides in response to major roadway incidents. Another strategy might be to provide comprehensive information to travelers about available transit options, such as comparative travel times to key destinations using car or transit.
The major value proposition of the I-210 Pilot for transit agencies is increased travel time reliability and improved transit ridership within the corridor through the coordinated use of existing assets and infrastructures. Indeed, one of the pivotal effects of congestion along the corridor is that transit agencies cannot provide transit services to the public with the travel time reliability riders want. This has a significant effect on customer service, as travel time reliability is a major factor in how travelers select a particular mode of transportation.
Using transit service effectively to support corridor operations will depend on several factors, including the ability to:
- Provide adequate parking near transit stations
- Use existing transit vehicles to accommodate additional passengers
- Put additional transit vehicles into service
- Monitor transit operations nearly in real time
- Coordinate operations among transit operators
- Communicate information to motorists and transit riders effectively
To effectively manage a transportation corridor, it is essential to have a clear picture of what is occurring in it. But the need for situational and operational awareness is complicated by the fact that both the capacity of transportation systems and the travel demand placed on those systems are somewhat dynamic. Arterial capacity, for instance, is heavily influenced by the operation of traffic signals at intersections. Roadway capacity can be influenced by incidents, construction and maintenance activities, inclement weather, and driver behavior. The capacity of transit services is a function of service frequency and type of vehicles used. Moreover, while travel demand is somewhat repetitive on a day-to-day basis, variations can occur over time. While there are obvious differences between weekdays and weekends, travel demand may fluctuate on a month-by-month basis and be influenced by business cycles. Up-to-date measurements of corridor performance and travel demand are therefore vital if agency operators are to respond effectively to corridor needs and determine appropriate pre-approved management strategies to meet specific, agreed-upon corridor performance metrics.
Achieving adequate situational and operational awareness requires the deployment of comprehensive supportive monitoring systems. Although many agencies have devoted substantial efforts to deploying real-time monitoring systems in their transportation networks, significant gaps remain in what is needed to adequately support the corridor-based performance and operational objectives of the I-210 Pilot. For instance, while extensive real-time monitoring capabilities already exist along the I-210 freeway, real-time monitoring along arterials is somewhat limited, with large variations from one operating agency to the next. Real-time information sharing between agencies is also only partially available.
A lack of sufficient monitoring can significantly impede operators' ability to devise optimal response strategies for operational issues. Similar to other aspects of this project, the development of a suitable real-time corridor monitoring system is a problem with multiple facets, including:
- The type of data that could be collected from freeway, arterial, transit, and other monitoring systems
- How frequently data can be retrieved
- How to validate and filter the collected information to remove erroneous data
- How to store and disseminate the collected information so corridor systems and stakeholders can use it
- How to visualize the collected information so it's easy to interpret
Coordinated Strategy Management
Once the situational awareness issues have been addressed, the problem of defining what to do under different operational environments arises. This is crucial, as a lack of coordination among corridor stakeholders can result in the implementation of less effective solutions than what might be achievable through coordinated control. In some cases, a lack of coordinated control may also be responsible for degrading corridor operations.
Regional transportation partners need to have an ability to define, select, communicate, and implement strategies that support jointly developed corridor management objectives and performance metrics. Effective coordination of different operational systems will require the establishment of agreed-upon processes and corridor performance metrics based on common operational philosophies and corridor management objectives. A need for such coordination exists as current corridor operations are typically fragmented. Each transportation system is typically managed as an independent system, with only occasional considerations given to cross-system or cross-jurisdictional issues. This prevents implementation of synergistic strategies through a coordinated ICM system.
Communication with System Users
A key part of improving overall quality of life along a corridor is to consistently meet system users’ reasonable expectations. This involves both meeting corridor performance metrics and communicating reliable information to travelers. Depending on the extent of the traffic management system developed, the information provided to travelers may include the location and severity of congestion hotspots, routing options around congestion hotspots or problem areas, data for transit services, and data for alternate trip options. The last option might, for instance, include providing comparative statistics for trips made by car or using transit, or for trips delayed by a certain amount of time. Information about the projected impacts of incidents or events could also be published to provide travelers advance information about future traffic conditions and enable them to respond well ahead of time to a given situation.
System Management and Monitoring
The effectiveness of traffic management is highly dependent on the quality and completeness of the information used to monitor the operations and performance of individual systems, and the ability to implement desired control actions. While suitable field equipment may be deployed to enable adequate information gathering and system control, these devices can degrade over time due to exposure to weather, traffic, construction activities, vandalism, or other causes. To maintain an appropriate level of operations, it is imperative to monitor deployed equipment continuously and advise system operators about equipment health. This may require developing methods and metrics for assessing equipment and overall system health based on the equipment status and the monitoring information.