Integrated corridor management offers transportation efficiency

Efficient traffic management can maximise utilisation of infrastructure assets and minimise delays and journey times for users

In the Intelligent Transportation Systems world, the concept of managing roadway or transportation corridors is not new. Smart Corridor concepts have existed for some time, such as the Santa Monica Smart Corridor system from the 1990s. Across the world, a new emerging model for operating roadway transportation networks called integrated corridor management (ICM) has emerged. This is particularly true in California, where several new ICM projects have or are being deployed. There is a new paradigm for corridor management and three project examples in California stand out.

All congested cities, urban areas and regions have problem corridors that are heavily used and problematic from the congestion management, safety and mobility standpoints. They are often the origin-destination passageways where people are commuting between a city centre and the key suburban areas where people reside. To manage these corridors, and the urban area as whole, agencies have upgraded technology systems to a high degree. This includes agencies that manage freeways, such as Departments of Transportation, arterials (municipalities), transit systems, toll systems (for managed lanes), as well as those agencies responsible for emergency response (police, fire and service patrols). Unfortunately, these agencies still typically operate in silos, only concerned about the optimal efficiency of their own facilities, modes or jurisdictions. ICM is the concept that breaks down the walls to enable both technically and institutionally the management of our transportation systems in a holistic manner that best benefits the problem corridor and all traversing through it. Through ITS technologies within the various transportation domains, combined with the latest systems integration, software and computing technologies, ICM can be better realised than any other time in the past.

ICM is an ITS concept designed to manage facilities and modes in a coordinated manner. It involves active traffic management and active transportation demand management to optimise use of available infrastructure. It includes methodologies for directing travelers to underused capacity and modes which involves schemes to focus motorists toward shifting departure times, routes, or modal choices. It also includes techniques to adjust capacity through transportation resources in the region.

Although the systems can vary, many components are common. All of these systems have monitoring tools to assess condition of facilities and assets, such as field devices and technologies. Another key component of these ICM systems is some sort of data portal or hub used to exchange information to and from the various subsystem and agencies. These also typically make use of response plans or decision support systems that make recommendations on how to respond. Many integrate performance measurement to evaluate in both real time and historically, how well the system has helped meet performance goals. The most advanced pro-active systems, such as the San Diego ICM, integrate network prediction and real-time decision micro-simulation tools so that the ICM DSS decisions are based not only on current conditions, but based upon what conditions will be, especially after the response plan is activated. On-line micro simulation tools provide strategy assessment to determine which plans will be most effective.

The Interstate 80 corridor in California’s Bay Area is the most congested corridor in the region and extends 34km from the Carquinez Bridge to Bay Bridge. Along this freeway and parallel arterials routes a variety of devices will be installed including lane use signs, variable advisory speed signs, highway advisory radio, traffic monitoring stations, information display boards, CCTV cameras, trailblazer signs, transit signal priority, and adaptive ramp metering. Real-time communications to these elements will be provided by a network of communications hubs linked to the 5246 Caltrans District 4 Transportation Management Center and other regional centers where advanced transportation management systems will be upgraded to include corridor-wide management of the freeways, arterials, and transit systems.

The San Diego, California ICM corridor is a congested north-south interstate corridor of Interstate 15 (I-15). This 34km stretch of road from SR52 in San Diego to SR78 in Escondido forms the primary artery for the movement of commuters, goods, and services from northern San Diego County to downtown San Diego. It is already a model for the deployment of the latest and evolving technologies for data collection, demand management and pricing strategies through its I-15 High Occupancy Vehicle express lanes project.  

Through this project, a system has been deployed to manage all facilities and modes in a pro-active, coordinated manner and optimises use of all available infrastructure, routes and modes. It involves integration of technologies and concepts that have yet to be used in the United States. Various Active Traffic Management strategies were deployed, including freeway coordinated adaptive ramp metering, signal coordination on arterials with ramp metering, regional arterial management and real-time multimodal decision support. They also include network traffic prediction, on-line micro simulation analysis, real-time response strategy assessment, en-route traveler information and pre-trip traveler information.

The South Bay region of Los Angeles County features three major, highly congestion corridors (I-105, I-405 and Route 110). Caltrans, in association with Los Angeles Metro (the project sponsor) and the South Bay Cities Council of Governments, is underway with the investigation, assessment and deployment of new integrated corridor management strategies in the region. A key focus is a system to coordinate arterial signals with the freeway’s adaptive ramp metering system. In addition, strategies will be assessed with the most effective selected for deployment and these include queue end warnings, adaptive traffic signal controls, junction controls, traffic demand management and new active traffic management strategies. They also include multimodal decision support systems, predictive travel time calculations, accident response strategy assessments and urban and interurban congestion management.