Automated Measuring of Cyclist/Motor Vehicle Post Encroachment Time at Signalized Intersections

Conflicts between motor vehicle and cyclists at a signalized intersection were characterized in this study using an objective conflict indicator; Post- Encroachment Time (PET). Traffic video data was collected for a total of 84 hours over nine days at two signalized intersections in the downtown area of Ottawa. PET was calculated using three different measurement methods, video timer measurement (MVTM) method, frame count measurement (MFCM) method and automated measurement (AM) method, for two types of conflicts, right-turn and left-turn.The movements “right, through and left” of a total 2736 cyclists have been observed. Cyclist stream interacted with a total of 4103 right-turn vehicles and 7701 left-turn vehicles. A total of 9384 conflict events for PET (0, 3] seconds between cyclists and vehicles were analyzed in this study. An automated video analysis technique was developed to measure the PET between cyclists and motor vehicles. The results of the conflict analysis showed that the average absolute error of PET between the MFCM and AM methods was 0.12 second and the standard deviation was 0.10 second. The evaluation results showed that there was a very good agreement in the PET classification of individual conflicts between the MFCM and AM methods. The classification was conducted by counting events with PET under conflict severity levels of 3.0, 2.0 and 1.0 16 seconds. The evaluation result showed that the coefficient of determination between the AM and MFCM methods was found to be 0.938. This study includes procedures to better interpret the conflict point of the motor vehicle and the cyclist in an automated manner (based on the geometry of the bounding box and direction of the travel), which appears to be a contribution for the analysis of cyclist-motor vehicle collisions.

• Supplemental Notes:
  • This paper was sponsored by TRB committee ANF20 Bicycle Transportation. Alternate title: Automated Measuring of Cyclist and Motor Vehicle Postencroachment Time at Signalized Intersections
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Kassim, Ali
  • Ismail, Karim
  • Hassan, Yasser
• Conference:
  • Transportation Research Board 93rd Annual Meeting
  • Location: Washington DC
  • Date: 2014-1-12 to 2014-1-16
• Date: 2014

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 19p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Bicycle crashes; Cyclists; Drivers; Field studies; Signalized intersections; Traffic conflicts; Traffic data; Video
• Uncontrolled Terms: Encroachment
• Geographic Terms: Ottawa (Canada)
• Subject Areas: Highways; Pedestrians and Bicyclists; Planning and Forecasting; Safety and Human Factors; I72: Traffic and Transport Planning; I83: Accidents and the Human Factor;

Filing Info

• Accession Number: 01515275
• Record Type: Publication
• Report/Paper Numbers: 14-2095
• Files: TRIS, TRB, ATRI
• Created Date: Feb 21 2014 3:18PM