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traffic signal standard


  • Traffic Signal Standards

  • HistoryChaosNEMA (TS 1)170 (CALTRANS / NY)170E179470iNEMA TS 22070ATC2070NMemory Plug-inOthers . . . ElectromechanicalIn the beginning..

  • Traffic Controllers Timeline1940s19761980s1992TS-2NTCIPElectro-mechanicalNEMATS-1170NEMATS-22070ATC19981990s

  • Electro-Mechanical ControllersNo standards in useNo software neededStill exists, New York City, Chicago, ( New York has over 11,000)

  • NEMA TS 1 & TS 2 ControllersFunctional specificationIncludes vendor-dependent hardware & softwareShelf mountedTS 1 standard pin-outs for A, B & C, but not DTS 2 provides for serial connection to cabinetProprietary solutions for signal timingWide variety of cabinet configurations

  • Type 170 & 179 ControllersHardware specificationSoftware is provided by othersRack mounted with standard modulesStandard front panelOriginally developed by public sectorVery low cost QPL approachUtilized older technology

  • Advanced Transportation ControllersThe ATC is attempting to bring these two competing standards together while preserving the best of both.170NEMAATC

  • ATC Program GoalsInterchangeability between manufacturersAssured source of competitively priced controllersBetter adaptability to advances in technologyCost effective and modular constructionMinimize the level of hardware detailEnsure interoperability within systemsProvide well defined controller testing requirements

  • ATC Program Goals (continued)Open architectureHardware and software platformSupport for multiple ITS applicationsRecoverable software investmentSoftware portability between vendors / technologyEnhanced availability of software applicationsFlexible hardware platformBetter adaptation to new technologyPromotes expandability for power usersTraffic control PC

  • Potential ATC ApplicationsTraffic SignalTraffic SurveillanceTransitCommunicationsField MasterRamp MeterVariable/Dynamic Message SignGeneral ITS BeaconsCCTV CamerasRoadway Weather Information Weigh in MotionIrrigation ControlLane Use Signals

  • The ATC Family of StandardsController Unit 2070-ATC and the ATCCabinet SystemApplication Programming Interface (API)Application Software

  • NTCIPNational Transportation Communications for ITS Protocol (NTCIP)Device level data dictionaries Communications protocols for transmissionBased on existing standardsInternet ProtocolsInternational Standards Organization (ISO) Open-Systems Interconnection (OSI) layersData element definition uses ASN.1 language

  • ITS StandardsMessageData ElementData ElementMessage Set StandardsData Element Standards Protocol StandardsData ElementData ElementCommunications

  • National ITS Architecture

  • Where do Traffic Signal Standards fit?

  • NTCIP Traffic Signal StandardNTCIP defines communications standards applicable to traffic signal controllersUsers define controller specificationsUsers define system operational characteristics

  • List of Required Traffic Signal StandardsDictionariesNTCIP 1201 Global Object DefinitionsNTCIP 1202 Actuated Signal ControllerProtocolsNTCIP 2301 AP-Simple Transportation Management Framework (STMF) ProfileNTCIP 2101 / 2102 Subnet ProfilesNTCIP 2201 / 2202 Transport Profiles

  • Bringing Things TogetherIn general, NTCIPUses modular standardsCovers multiple devicesDevices will need multiple compatible standardsSimply specifying NTCIP-Compliant is not enough..

  • Web Resourceswww.ntcip.orgNTCIP Guide, Case Studies, Library Standards list, details, fact sheetsStandards Development


    Delivery: (0.5 minute)

    We have just heard about some new system deployments and case studies.

    I want to cover a little about the history of traffic signal controllers and where the industry is headed with respect to controller and cabinet standards.

    Then, I want switch over and discuss NTCIP Traffic Signal communication standards. NTCIP stands for National Transportation Communications for ITS Protocol. Delivery: (0.5 minutes)

    You have likely heard of the Advanced Transportation Controller (ATC). The effort underway is bringing the transportation industry the next generation of multipurpose controller that combines best of the NEMA and 170 worlds.

    It is the descendant of line of what to used to be machines strictly used for traffic signals. Since the advent of the Type 170 controller and its ability to accept custom programs, this has begun to change.

    The Type 170 has been used for a variety of applications from ramp meters to irrigation control. Also with the coming of more advanced computing power and the use of higher level programming languages, the door for innovation has opened up.

    The ATC will likely be harnessed for many new transportation applications.Delivery: (1 minute)

    Here is a timeline of traffic controllers.

    Electro-Mechanical-since 40s-without softwareNEMA TS 1 Standard 1976 -with proprietary softwareNEMA TS 2 Standard 1992 -with proprietary softwareNEMA TS-2 standard with NTCIP-1998 - with proprietary software but open communications170 Family since the early 1980s purchase softwarefrom two outside vendors or develop software in-houseATC family, including 2070-90s- purchase software from over six outside vendors or develop software in-house

    Delivery: (1 minute)

    In the early days of traffic signal control, we used an electro-mechanical controllers. They have clock wheels and programming pins.

    In the early 1970s there was an emergence of the modern traffic controllers that we know todaythe NEMA and the 170-style controllers.

    New York city, with 11000 traffic signals, relied on electromechanical traffic controllers, but today they are engaged in developing and purchasing traffic controllers that are standards-based using NTCIP ona massive scale.

    Delivery: (0.5 minutes)

    The NEMA controllers have always provided a packaged deal that includes both hardware and software.

    For many users, a turn-key controller makes for easier procurement.

    The growing need for interconnected signals and centralized systems could only be met as long as a user keeps buying units from the same manufacturer.

    Without a standard D connector and common communication protocol, NEMA controllers did not talk to other NEMA controllers.

    Note on the slide, that the TS2 controller has a serial control connection to the cabinet equipment this is being carried to the ATC standard.

    Delivery: (0.5 minutes)

    In 1978, along with the FHWA, NYSDOT & CALTRANS issued the "Type 170 Traffic Signal Controller System- Hardware Specification" (IP-78-16).By standardizing the hardware, these units:1) Allowed multiple software applications such as intersection control, Ramp metering, or On Street Master control.

    2) Reduced maintenance costs and provided easier tests for initial acceptance and troubleshooting (you test the controller with the software STEP test, you only tested your signal control program once)

    3) Both states provided their own software for these controllers and outside vendors such as BiTran Systems, Kentronics and Wapiti began to provide software for these units.Delivery: (2 minutes)

    Today, we see the emergence of a new traffic signal controller standard. The ATC is being developed under the ITS Standards Program. Both users and manufacturers are working cooperatively to bring together the best concepts from the NEMA and 170 worlds to create a field controller platform that will serve many ITS functions.

    The real power of the concept is that either community can make use of this new hardware. Its the best of both worlds.

    Delivery: (0.5 minutes)

    Program Goals for the ATC

    Interchangeability between manufacturers Think PCBetter adaptability to advances in technology the 170 was not very adaptableEnsure interoperability within systemsProvide well defined controller testing requirements

    Delivery: (0.5 minutes)

    This side is basically explaining that you can replace the controller and keep the software or replace the software and keep the controller.

    With a modular construction, you can buy an additional Input Module if you install more detection.

    Need more power for that new adaptive program? Just replace the CPU Module or add more memory.

    Think of the ATC as your Traffic control PC

    Delivery: (1 minute)

    Here is a list of the potential applications that the ATC could service. However, it is expected that the majority of these units will be put in to service as traffic signal controllers.

    Delivery: (1 minutes)

    The ATC system has four major components:

    The controller unit is the main brain of the system and directs all of the functions of the installation

    The cabinet system provides support for operation of the controller, it includes all inputs, outputs, communications and power supply as well as protection from the elements.

    The Application Programming Interface is a piece of software that separates the application from the OS and hardware.

    The application is the actual program such as a traffic signal program or a VMS controller program.

    The ATC controller standards originated from the CalTrans 2070 specification. Consider the California standard as sort of first generation. Then, an effort was begun to enhance the original specification and make it generic, sort of removing CalTrans and creating a document that any state or agency could use. T