Impacts of signal system timings on rain related congestion.

Details

• Creators:
  Sullivan, Andrew J. ; Sisiopiku, Virginia P. ; Reddy-Surhabi, Suman
• Corporate Creators:
  University Transportation Center for Alabama
• Subject/TRT Terms:
  • Traffic signal timing
  • Traffic congestion
  • Congestion management systems
  • Rain traffic signals, closed-loop signal systems, weather-related congestion
• Publication/ Report Number:
  UTCA Report 07211
• Resource Type:
  Tech Report
• Geographical Coverage:
  Alabama
• Corporate Publisher:
  University Transportation Center for Alabama
• Abstract:
  It is known that inclement weather can affect traffic volumes, vehicle speeds, speed variance, saturation flow rates, and sometimes ; discharge rates from traffic signals. These parameters in turn can have a significant impact on the efficiency of traffic signal ; timing plans. Timing plans developed for dry conditions with good visibility may not be as effective under wet conditions with ; poor visibility, even for the same traffic volumes. Previous studies have looked at the effects of poor weather on traffic signal ; efficiency but they have focused primarily on winter weather conditions involving snow and ice, which have much more dramatic ; impacts on traffic flow. In regions like the South, rain is the primary adverse weather event and even though its effects on traffic ; flow may be smaller than snow or ice, its impacts can still be seen. ; This study sought to assess the impact of rain on traffic flow and determine whether there can be a meaningful benefit to ; developing and implementing signal timing plans specifically for rain events. Using simulations for two study corridors in ; Birmingham, Alabama, it was found that moderate and heavy rain events do impact traffic flow, increasing stops and average ; delays up to 6% compared to dry conditions. Signal timing plans optimized for wet conditions were found to reduce these delays, ; though in absolute terms the benefits were modest. It was found, however, that the effectiveness of rain-specific timing plans ; depended to a large extent on prevailing traffic volumes. An evaluation of potential costs and benefits resulting from rainoptimized ; signal timing plans found that the net benefits, at least in the two study corridors, are questionable. The analysis found ; that projected costs over a five-year life cycle would significantly exceed potential benefits. Rain-specific timing plans may have ; useful applications in certain corridors but the potential benefits and costs should be carefully evaluated beforehand.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/18549/dot_18549_DS1.pdf
• File Type:
  [PDF - 555.07 KB]
• Collection(s):
  University Transportation Centers ; US Transportation Collection
• Main Document Checksum:
  urn:sha-512:6c30d45ad8d65a1d8550e95b119e332a32d924877d21e271716bfa935336e6f98f99cad15d38dee4a32d88d9401662e9635357459ccddf0aa8821657713c0004