The Discrepancy between Actual Operating Speed and Drivers’ Self-Reported Speed

Self-reporting is a valuable tool in transportation research practices especially in drivers’ non-compliance behavior on- and off-road. Self-reporting often serves as a proxy and provides access to data that may be difficult to obtain by other means. Whereas assessment and validation of such subjective observations is another challenge to decipher, objective measures of drivers’ behavior (i.e. speed behavior) could be useful to assess the correlation with self-reported data. To appraise the reliability of drivers’ self-reported data, this study was conducted to analyze drivers’ perceptions of their driving speed and compare it with the actual operating speed. Data was collected for the Seward Highway in Alaska; a two-lane highway that connects Anchorage with Seward. The actual operating speed data and the self-reported data were collected at passing lanes sites where a strategy of differential speed limits was recently implemented. Similarly, to model drivers’ self-reported attitude data, a seemingly unrelated regression (SUR) was used to account for contemporaneous correlation of error terms and the endogenous behavior of variables in the system of equations. Mean free-flow speeds were compared to the expected means of the drivers’ self-reported speeds using one-way ANOVA. In terms of operating speeds, the results suggested that the actual speeds of vehicles in the passing lanes were higher than the current posted speed limits (PSLs). The results of the statistical analysis indicated a significant discrepancy between the actual operating speeds and the drivers’ self-reported speeds. The findings of this study could have significant implications on the implementation of PSLs, and regarding the perception of drivers about their own speeding behavior on two-lane highways and the passing lanes, which may be addressed to improve safety. The drivers may be educated about PSLs, to improve traffic safety and operations and strategies be devised to better reduce the above-stated discrepancy.

• Record URL:
  • https://doi.org/10.1061/9780784482575.020
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/9780784482582
• Supplemental Notes:
  • © 2019 American Society of Civil Engineers.
• Corporate Authors:

  American Society of Civil Engineers

  1801 Alexander Bell Drive
  Reston, VA  United States  20191-4400
• Authors:
  • Raza, Sajid
  • Abaza, Osama
  • Safi, Fazal R
  • Hussain, Arshad
• Conference:
  • International Conference on Transportation and Development 2019
  • Location: Alexandria Virginia, United States
  • Date: 2019-6-9 to 2019-6-12
• Publication Date: 2019-8

Language

• English

Media Info

• Media Type: Web
• Pagination: pp 199-212
• Monograph Title: International Conference on Transportation and Development 2019: Innovation and Sustainability in Smart Mobility and Smart Cities

Subject/Index Terms

• TRT Terms: Behavior; Cross correlation; Data collection; Drivers; Speed; Statistical analysis
• Identifier Terms: Seward Highway (Alaska)
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors;

Filing Info

• Accession Number: 01729981
• Record Type: Publication
• ISBN: 9780784482582
• Files: TRIS, ASCE
• Created Date: Feb 3 2020 7:58AM