Investigating the Impacts of Green Signal Countdown Devices: An Empirical Approach and Case Study in China
This paper presents an extensive investigation regarding the impacts of green signal countdown devices (GSCD) on the intersection safety and efficiency, based on field observation of critical driver and vehicle related parameters at two similar intersections (one with GSCD and the other without GSCD) in Shanghai. Statistical analysis results have revealed that the installation of GSCD can 1) encourage drivers to pass the stop-line during the yellow phase with higher speeds, and thus result in better utilization of the yellow phase and increased capacity of the intersection approach; 2) smooth the driver's response to the phase transition and effectively prevent the sudden change of speeds; 3) effectively eliminate the intersection dilemma zones by allowing the drivers to envision the phase transition and make decisions in advance; and 4) significantly reduce the number of red-light violations. Despite its effectiveness in facilitating the driver decision-making process, the installation of GSCD may adversely increase the possibility of collisions with unexpected crossing vehicles or pedestrians due to the significantly increased speeds of vehicles approaching the yellow phase. The analysis results from this study will offer the basis for traffic practitioners, researchers, and authorities in China to assess the impact of GSCD with respect to its operational and safety performance, and propose guidelines for its proper field installation.
-
Corporate Authors:
500 Fifth Street, NW
Washington, DC United States 20001 -
Authors:
- Ma, Wanjing
- Liu, Yue
- Yu, Jie
-
Conference:
- Transportation Research Board 89th Annual Meeting
- Location: Washington DC, United States
- Date: 2010-1-10 to 2010-1-14
- Date: 2010
Language
- English
Media Info
- Media Type: DVD
- Features: Figures; Photos; References; Tables;
- Pagination: 17p
- Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD
Subject/Index Terms
- TRT Terms: Clearance interval (Traffic signal cycle); Empirical methods; Green interval (Traffic signal cycle); Operations; Red light running; Statistical analysis; Traffic signal cycle
- Geographic Terms: Shanghai (China)
- Subject Areas: Highways; Safety and Human Factors; I85: Safety Devices used in Transport Infrastructure;
Filing Info
- Accession Number: 01152382
- Record Type: Publication
- Report/Paper Numbers: 10-1578
- Files: TRIS, TRB
- Created Date: Mar 16 2010 6:13AM