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Applied Public Works Research The APWA Donald C. Stone Center for Leadership Excellence in Public Works
The mission of the APWA Donald C. Stone Center for Leadership Excellence in Public Works (DCS Center) is to position public works professionals for the twenty-first century. In keeping with this important goal, the APWA Reporter features a section dedicated to applied research in public works. This section, published quarterly, provides insight into thoughtful analysis of issues and opportunities based on applied scientific research methods as a way of further contributing to the body of knowledge. Many of the articles appearing in this section are capstone papers written by participants in the DCS Center Level 3 Public Works Executive (PWE) Program. Other research articles are selected based on the applied nature of the paper and its relevance to public works. Researchers interested in submitting articles should visit the website http://www.apwa.net/donald-c-stone/DonaldC-Stone-Center/Public-Works-Research to learn details of the requirements for publication. Articles submitted to the “Applied Public Works Research” section of the Reporter will be reviewed by an expert group of professionals and academicians. Depending on the technical aspect of a submission, a summary to highlight how the research can be applied may be requested. These will appear as “Research Application Summaries” appearing after the abstract. The 150-word abstracts of approved articles will be published quarterly. The full-length articles, as listed below, can be accessed via the link provided with each abstract. This issue of the Reporter highlights two articles that fit the requirements for this section. The papers were presented at the Transportation Research Board’s 2012 Annual meeting. Disclaimer: The views and opinions expressed in these papers are solely those of the authors and may not represent those held by APWA or the entities referred to in the articles. Are Roundabouts Environmentally Friendly? An Evaluation for Uniform Approach Demands Authors: Meredith Jackson, Hesham A. Rakha Source: Transportation Research Board Annual Meeting 2012 Paper #12-0789 Date: January 2012 APWA URL: http://www.apwa.net/donald-c-stone/Donald-C-Stone-Center/Public-Works-Research/Applied-Research-Articles
With an increased prevalence of roundabouts in the United States, including roundabouts in the design alternatives can be beneficial from an efficiency, safety, and environmental standpoint. Studies have compared roundabouts with other intersection control strategies; however, they are restricted to specific cases. These studies have suggested that when using environmental measures of effectiveness roundabouts can have few emissions and lower fuel consumption levels when compared to unsignalized intersections and can be better for lower demands than signalized intersections. However, some studies have not found this to be the case. In this study a generalized intersection with four single lane approaches with equal demand on all approaches was modeled to determine the control with the least fuel consumption, carbon dioxide, carbon monoxide, hydrocarbons and nitrogen oxide emissions. This study demonstrates that fuel consumption and CO2 emissions depend upon turn demand and overall demand. Roundabouts can reduce fuel consumption and CO2 emissions when left turn demands are lower than 30% of the overall demand or when left turn demand is less than 50% of the overall demand and right turn demand is greater than 10%. For most demands and turning ratios, roundabouts can also improve CO, HC and NOx emissions over traffic signal, two-way stop, and all-way stop control alternatives. 20 APWA Reporter
October 2012
