Powell Boulevard in Portland, OR.

Details

• Creators:
  Figliozzi, Miguel ; Monsere, Christopher ; Slavin, Courtney ; Albright, Eric ; Feng, Wei ; Moore, Adam
• Corporate Creators:
  Portland State University. Department of Civil & Environmental Engineering
• Corporate Contributors:
  United States. Department of Transportation. Research and Innovative Technology Administration
• Subject/TRT Terms:
  • Highway traffic control systems
  • Urban highways
  • Highway corridors
  • Traffic volume
  • Traffic signal timing
  • Air quality
  • Traffic flow
  • Travel time
  • Bus priority
  • Bus transit
• Publication/ Report Number:
  OTREC-RR-13-07
• Resource Type:
  Tech Report
• Geographical Coverage:
  Portland (Oregon)
• Corporate Publisher:
  Oregon Transportation Research and Education Consortium
• Abstract:
  The Sydney Coordinated Adaptive Traffic System (SCATS) is used to mitigate traffic congestion along urban arterial corridors. Although there ; has been research on SCATS’ performance, this report combines three different areas of research about SCATS that are not known to be ; represented in any research literature. These include: (a) the relationship between SCATS, traffic volumes, and Transit Signal Priority (TSP); (b) ; between TSP and traffic conditions; and (c) the correlation between signal timing and air quality; in particular, human exposure to the air pollutant ; PM2.5 at intersections. In addition, this research looked at the key factors affecting transit user exposure to traffic-related pollutants at bus shelters. ; All areas of study present the results of statistical tests and regressions to determine SCATS or traffic variables impacts. ; SCATS did show statistically significant improvements regarding traffic speeds at one minor intersection, even when traffic volumes showed a ; statistically significant improvement. At a major intersection, results were mixed and not conclusive. Overall, it was determined that the ; improvements available through SCATS vary depending on the time of day and the direction of travel. TSP was not negatively affected by ; SCATS. In controlling for both priority and traffic conditions, each were shown to have a distinguished and significant impact on bus travel time. ; Non-priority signals had a much greater impact on travel time than priority signals (11.0 and 0.6 seconds for the corridor model, respectively). In ; controlling for both priority and traffic conditions, each were shown to have a distinguished and significant impact on travel time. Utilizing a ; regression model, results in an intuitive ranking of the intersections’ delay was produced; major intersections with high traffic volumes on ; crossing streets are likely to not experience TSP benefits. ; To a high degree, this research has shown that pedestrian exposure can be considered as an outcome of traffic-signal timing decisions made by ; cities and counties. The statistical results have shown the high impact that signal timing and queuing have on pedestrian level exposure. Heavy ; vehicle volume was a significant variable as well as the presence of buses. The reduction of bus idling time through more efficient operations and ; transit-signal priority is likely to reduce pedestrian and transit users’ pollution exposure levels. Longer green times along the main corridor are ; able to significantly reduce particulate matter for transit users and pedestrians waiting at the sidewalk of the intersection, whereas time allocated to ; cross the street increases queuing and exposure along the main corridor. The impact of heavy-duty diesel engines is also clear. The reduction of ; bus idling time through more efficient operations and transit-signal priority is likely to reduce pedestrian and transit users’ pollution exposure ; levels. Transit agencies can also reduce pollution significantly by improving the efficiency and cleanliness of their engines. TriMet (the local ; transit agency) initiatives to improve fuel efficiency by installing EMP engine-cooling devices not only improve fuel efficiency, but also air ; quality. Finally, significant reductions in transit users’ exposure to traffic-related pollution can be made at bus stops by properly orienting the ; shelter and by reducing bus idling.
  More +
• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/26122/dot_26122_DS1.pdf
• File Type:
  [PDF - 3.71 MB]
• Collection(s):
  University Transportation Centers ; US Transportation Collection
• Main Document Checksum:
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