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ITS Communications: Implementing the NTCIP Standard

ITS Communications: Implementing the NTCIP Standard Experiences from City of Baltimore Signal integration May 9, 2006 Diederick VanDillen diederick.vandillen@itssiemens.com 410-744-8228. Presentation Outline. Baltimore Project Overview NTCIP Integration Approach

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ITS Communications: Implementing the NTCIP Standard

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  1. ITS Communications: Implementing the NTCIP Standard Experiences from City of Baltimore Signal integration May 9, 2006 Diederick VanDillen diederick.vandillen@itssiemens.com 410-744-8228

  2. Presentation Outline • Baltimore Project Overview • NTCIP Integration Approach • Challenges and Lessons Learned • Summary

  3. Baltimore Project Overview • Siemens (System Integrator and central software) • Naztec NEMA TS-2 Type 1 controllers • 1300 Signals • CCTV, DMS, Transit Priority • Existing twisted wire pair, 2-wire, half duplex field communications

  4. NTCIP Integration Approach • Communications Testing and Evaluation • Identify compatible modem and determine maximum drops per channel at 1/sec resolution • Higher speed modems different characteristics on existing cable • GDI 19.2FSK modems with up to 10 drops per channel • Compatibility with multiplexed DSL data for video • GDI 9.6kbps DSP modems with up to 6 drops per channel

  5. NTCIP Integration Approach • NTCIP 1201 (Global) and 1202 (ASC) primary standards • SNMP GET / SET for upload/download, time broadcast, pattern commanding, and dynamic object configuration • STMP dynamic objects for status polling – multiple can be defined • 1/sec status polling (e.g. green/red, coordination status, alarms) • 1/30 sec system detector polling (volume, occupancy) • Intersection cutover by communications circuit from City perimeter toward CBD

  6. Challenges & Lessons Learned • Licensing • Restricted access to Naztec proprietary MIBs required a 3-way licensing agreement between City, Naztec and Siemens • Establish early so not to delay schedule

  7. Challenges & Lessons Learned • NTCIP standards mismatch – Controller specification predated system integration specification by about 2 years • Block objects not yet defined – no proprietary or standard block object support • Some objects (coordOffsetTransition) not supported by older NEMA TS3.2 spec. • Some standards interpretation issues (SNMP vs. NTCIP variable binding rules)

  8. Challenges & Lessons Learned • Communications Performance • NTCIP not as efficient as some proprietary protocols • Upload/Download times (120 second constraint) and channel loading to support 1/sec status polling

  9. Challenges & Lessons Learned • Standard MIB objects ensure higher level of interoperability • Use standard objects to support most functions • Compliant devices will at least communicate at this level • Standard maintained by standards body with process for review, approval, updates, arbitration

  10. Challenges & Lessons Learned • Manufacturer specific MIB objects only where necessary • Implement non-standard features (i.e. remote download) • Custom software to decode and process objects (Hidden costs & risks) • Increase complexity in system integration • Higher maintenance cost for proprietary features

  11. Challenges & Lessons Learned • Design • Object Map – table that relates MIB object parameters to controller screen parameters for design and verification • Central software design isolates components with access to proprietary MIBs - software distribution restrictions

  12. Challenges & Lessons Learned • Testing – Lots! • System integration testing • Status polling, commanding, cabinet alarms • Upload / Download – toggle & verify each parameter • Independent compliance testing using 3rd party tools (IDI Tester, FTE NTCIP protocol analyzer) helped isolate and identify problems • Retest with each new release of controller firmware and central software • Lab and proof-of-concept test locations

  13. Challenges & Lessons Learned • Operations • Second-second control (pre-UTCS) toward distributed/centralized control • Maintain offset/progression and common clock reference between system boundaries during cutover

  14. Summary • Baltimore is one of the largest NTCIP implementations with 961 traffic signal controllers integrated to date • Multi-vendor integration forces compliance and ensures a more complete open solution • NTCIP is ready for deployment

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