Department of Public Works

Gateway Cities Traffic Signal Synchronization and Bus Speed Improvement Project

The I-5/Telegraph Road Corridor is an LA County ITS project, which will result in arterial infrastructure improvements along Telegraph Road in the Gateway Cities Forum. The I-5/Telegraph Road Corridor consists of 277 intersections in 10 different jurisdictions, comprising 8 cities, the County and Caltrans.

The objective of this project is to design, develop and deploy traffic control systems in the corridor such that the signals along the I-5/Telegraph Road can be synchronized across the jurisdictional boundaries. This project will concentrate on the needs of the agencies in this corridor with respect to signal synchronization along the Telegraph Road and recommend improvements to field infrastructure (including controllers, loops, detectors, communications) and central traffic control systems to meet those needs.

When successfully completed, each of the agencies responsible for traffic signal operations in the I-5/Telegraph Road Corridor will have full access to a TCS that provides monitoring and control of the traffic signals under its jurisdiction. Agencies will be able to synchronize their signals with neighboring agencies and exchange traffic information in real-time. Agencies will also be able to exchange data with other agencies in the Gateway Cities region. This will allow the agencies to respond to recurrent and non-recurrent congestion in a coordinated fashion across the jurisdictional boundaries.

The project will be implemented in the following phases:

  • Phase 1: Conceptual Design Master Plan
  • Phase 2: Detailed Design / System Implementation

The major components of this project are:


  • Advanced Traffic Management System (ATMS)

    This component consists of the development, design, selection, and implementation of a complete inter-jurisdictional ATMS. The ATMS will include the hardware and software necessary to allow monitoring, controlling, and coordinating the operation of traffic signals and, in the future, other Intelligent Transportation Systems (ITS) field devices along Telegraph Road. The system will be operated from individual agency work stations which will have traffic surveillance capabilities through detecting and monitoring signal status, traffic congestion and incidents, and will display this information through a fully integrated mapping function. The system will also be able to detect equipment malfunctions which will enable the operator to initiate appropriate maintenance operation responses and various other responses to traffic events and congestion either manually or automatically using an expert system application.

    It is anticipated that the system will provide once-per-second monitoring of traffic signals, inter-jurisdictional communication with localized control, and levels of security to restrict access to unauthorized users. The system will also employ strategies such as inter-jurisdictional data sharing, cooperative efforts in timing plan development, a coordinated response to arterial incidents, congestion and special events, and traffic data analysis. Additionally, the system will provide local and regional level access, controls, and connections to the future I-105 Corridor Traffic Management Center (TMC), and other future regional traffic forum TMCs, the City of Los Angeles’ ATSAC System, Los Angeles County TMC, and Caltrans Districts 7 and 12 TMCs.

    As part of this component, each municipality will be provided with work stations capable of controlling its jurisdiction’s traffic signals, as well as the ability to monitor all signals along the I-5/Telegraph Road Corridor from its remote work station site. Also, provisions shall be made to allow an individual city to control other jurisdiction’s signals full time or during non-peak hours and weekends. These control strategies will be accomplished by the execution of multi-jurisdictional agreements. Typically, a work station will consist of a computer system located at each jurisdiction’s city hall or other location and will be fully capable of satisfying that jurisdiction’s traffic management needs, as well as the requirements of the project in general. This component will provide the hardware and software necessary to provide these capabilities to each I-5/Telegraph Road Corridor Agency.

    For all jurisdictions in the Corridor with existing traffic control systems, an analysis will be completed to determine the need for replacement or modification of their respective systems. In the event that the project recommends, and the city desires to maintain its system, then the ATMS will provide an interface and any required equipment to enable communication and insure compatibility with the other jurisdictions in the Corridor. In this instance, the ATMS will be a hybrid system that will consist of a combination of new and existing systems.

    Another element of the ATMS is the establishment of a comprehensive Vehicle Detection System for the Corridor to supplement the existing traffic signal detectors and to collect real-time traffic data and information at key intersection locations where monitoring of traffic is critical to the movement of vehicles. The amount, type, and location of system detectors will be determined after careful consideration of the user needs, system functional requirements, and available budget.

    Although an Advanced Traveler Information System (ATIS), Closed Circuit Television (CCTV) cameras, Changeable Message Signs (CMS), and other ITS elements are not part of this project, the ATMS must be capable of accommodating the installation of these elements in the future, and be able to provide the necessary control, map display, and monitoring functionality.

    The development of this project will require a traffic management system operations plan which will identify the existing and the desired level of operation, and recommend the most suitable ATMS to fit those needs. This will require the selection and implementation of Commercial Off-the-Shelf (COTS), or other previously developed, advanced traffic management system software capable of interfacing with the Countywide Architecture currently under design by Los Angeles County.


  • Local City Control Site

    This component will include a schematic floor plan, facility specification, staffing, training and operations and maintenance requirements of a typical local city control site. A preliminary site for each city's control site will be identified. This will include conducting an on-site inspection and making recommendations on necessary alterations to this work space to provide the needed functionality. Future phases, will see the installation of the control sites for the affected agencies.
  • System Integration

    This comprises the integration of all the project’s components to ensure an open system architecture is maintained and that components are integrated in a seamless environment with a common interface. The ATMS must have the ability to interface with all related ITS elements implemented through other projects such as other regional traffic forum projects, other city systems, Caltrans systems, and all Southern California ITS Priority Corridor Steering Committee projects, such as the Showcase Project. The local city control sites must also be integrated with future subregional TMC(s) in the Gateway Cities Forum, Los Angeles County, and Caltrans Districts 7 and 12. The system must also be integrated and compatible with the Countywide Architecture currently under development by DPW’s consultant under the San Gabriel Valley Signal Operation and Maintenance (SOM) Pilot Project.
  • Communication System

    This comprises a communication system capable of supporting the recommended inter-jurisdictional ATMS design. The installation of a communications network is essential to support the traffic signal operation, monitoring, and control capabilities of the ATMS, as well as information exchange with other jurisdictions, stakeholders, and systems. These may include the State of California Department of Transportation (Caltrans) Freeway Management System, Los Angeles County arterial traffic control system, and other existing and planned systems outside the Gateway Cities area.

    This communication network must include links between the field infrastructure units (such as the system detectors and controllers) and each jurisdiction’s traffic control site. Additionally, it must include communication links between each local city site and any regional or sub-regional control site, such as the Gateway Cities I-105 Corridor TMC and the County of Los Angeles TMC.

    Since the communication system will drive the capability of all system components, both present and future ITS elements must be considered in the design. Additional primary considerations must be the expandability to include other potential stakeholders and users, system expansion to include additional signals, and the cost effectiveness of the system. Possible communications medium technology may include, but not be limited to, twisted pair cable, leased telephone lines, fiber optic cables, spread spectrum radio, very small aperture terminals, or a combination of the above.
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