Failure Analysis of Network Based Accessible Pedestrian Signals in Closed-Loop Operation

The potential failure modes of a network based accessible pedestrian system were analyzed to determine the limitations and benefits of closed-loop operation. The vulnerabilities of the system are accessed using the industry standard process know as Failure Modes and Effects Analysis. This analysis reveals that because the closed-looped operation increases operational observability, there is only one failure mode that is not detectible. Investigation on reliability of hardware and software indicate that the probability of this particular event is extremely low. The three primary components of a distributed real-time control system are hardware, software, and communications. Environmental conditions are the predominant factors that determine hardware reliability. The system was tested for its ability to function in the presence of electrical transients specified the NEMA. All hardware components meet or exceed NEMA temperature requirements. Software errors are difficult to detect and difficult to predict. Best practices in development and testing can minimize the number of errors. Testing includes multiple years of both laboratory and field testing.

• Record URL:
  http://www.webs1.uidaho.edu/niatt/research/Final_Reports/KLK719_N11-02.pdf
• 
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/34437
• Supplemental Notes:
  • This document is disseminated under the sponsorship of the Department of Transportation, University Transportation Centers Program.
• Corporate Authors:

  National Institute for Advanced Transportation Technology

  University of Idaho, Moscow
  115 Engineering Physics Building
  Moscow, ID  United States  83844-0901

  Research and Innovative Technology Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Wall, Richard
  • Johnson, Brian
  • Kyte, Michael
• Publication Date: 2011-3

Language

• English

Media Info

• Media Type: Print
• Edition: Final Report
• Features: Appendices; Figures; References;
• Pagination: 25p

Subject/Index Terms

• TRT Terms: Feedback control; Pedestrian safety; Pedestrian vehicle interface; Traffic control devices; Traffic signal control systems; Warning devices for persons with disabilities
• Uncontrolled Terms: Accessible pedestrian signals
• Subject Areas: Operations and Traffic Management; Pedestrians and Bicyclists; Safety and Human Factors; I73: Traffic Control; I85: Safety Devices used in Transport Infrastructure;

Filing Info

• Accession Number: 01343237
• Record Type: Publication
• Report/Paper Numbers: N11-02, KLK719
• Contract Numbers: DTRT07-G-0056 (Grant)
• Files: UTC, TRIS, USDOT
• Created Date: Jun 22 2011 12:44PM