operations at two-way long temporary work zones.

Details

• Creators:
  Schrock, Steven D. ; Patil, Shivraj S. ; Fitzsimmons, Eric J. ; Sarikonda, Vishal R.
• Corporate Creators:
  University of Kansas. Dept. of Civil, Environmental and Architectural Engineering
• Corporate Contributors:
  Kansas. Dept. of Transportation. Bureau of Research
• Subject/TRT Terms:
  • Work zone traffic control
  • Traffic signals
  • Portable equipment
  • Red light running
  • Flaggers
  • Portable Traffic Signals
  • Pilot Car Operations
  • Work Zones
• Publication/ Report Number:
  KS-16-02
• Resource Type:
  Tech Report
• Geographical Coverage:
  Kansas
• Corporate Publisher:
  Kansas. Dept. of Transportation. Bureau of Research
• Abstract:
  The primary objective of this study was to evaluate the use of Portable Traffic Signal (PTS) systems at long, rural ; two-lane work zones and to compare three different conditions for controlling one-lane traffic in conjunction with pilot car ; operations: flagging only, a PTS system with the presence of a flagger, and a PTS system without the presence of a flagger. ; The primary measures of effectiveness were determined as Red Light Running (RLR) violation percentages, vehicle delay ; estimates, queue lengths, signal timing operations, and general field operations. Data were collected three days per week ; over a period of four weeks from August 5, 2014, to August 28, 2014, at four different temporary work zones in Kansas. ; Two PTS units were used for the purpose of the study in conjunction with pilot car operations. ; It was found that the percentage of violations for the flagger only, PTS with a flagger, and PTS without a flagger ; were 1.1, 1.3, and 3.1 percent, respectively. A test of proportions conducted on the three samples at a 0.05 level of ; significance indicated that there was a statistically significant difference in the number of violations when a PTS was used ; with a flagger and without a flagger, as compared to when flagging only operations were used. Similarly, there was a ; statistically significant difference in the number of violations when a PTS was used with a flagger and when a PTS was used ; without a flagger. It was also found that there was no statistically significant difference between the number of RLR vehicles ; that followed an already departed queue for the PTS with a flagger and PTS without a flagger conditions. It was found that ; there was a statistically significant difference in the number of RLR vehicles that left the stopped queue and the number of ; vehicles that disregarded the PTS control for both the conditions. ; An exploratory delay analysis indicated that the presence of a flagger reduced the total delay by approximately 5 ; percent of the delay that could have occurred during the normal operations when flaggers waved the vehicles through the red ; light. Finally, equations were developed to determine the volume thresholds at which the PTS system would fail and the ; appropriate green intervals needed to serve a certain queue length. It was found that based on the existing KDOT policy of a ; maximum pilot car roundtrip time of 15 minutes, the PTS system would fail at an annual average daily traffic (AADT) of ; approximately 7,083 vehicles per day and at a corresponding maximum green time of approximately 446 seconds. ; In conclusion, it was recommended to use a PTS unit without a flagger in conjunction with pilot car operations at ; long, rural two-lane work zones but other measures were suggested, such as engineering studies to more accurately estimate ; queue lengths, installation of static signs indicating the expected wait time, and regular inspections of the PTS units by site ; supervisors or crew members to mitigate excessive delays and monitor for RLR vehicles.
  More +
• Format:
  PDF
• Funding:
  C1979
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/30782/dot_30782_DS1.pdf
• File Type:
  [PDF - 3.98 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:1203aa3977e8197e19f3396c783ef2cba3e62ac783589d0d377f83d2b9dd2c29