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Alex Bigazzi, Miguel Figliozzi, Portland State University
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Adam Moore: Bus Stop Air Quality: An Empirical Analysis of Exposure to Particulate Matter at Bus Stop Shelters
Congested traffic corridors in dense urban areas are key contributors to the degradation of urban air quality. While waiting at bus stops, transit patrons may be exposed to greater amounts of vehicle-based pollution, including particulate matter, due to their proximity to the roadway. Current guidelines for the location and design of bus stops do not take into account air quality or exposure considerations. This study compares the exposure of transit riders waiting at three-sided bus stop shelters that either: 1) face the roadway traffic or 2) face away from the roadway traffic. Shelters were instrumented with air quality monitoring equipment, sonic anemometers, and vehicle counters. Data were collected for two days at three shelters during both the morning and afternoon peak periods. Bus shelter orientation is found to significantly affect concentration of four sizes of particulate matter: ultrafine particles, PM1, PM2.5, and PM10. Shelters with an opening oriented towards the roadway were consistently observed to have higher concentrations inside the shelter than outside the shelter. In contrast, shelters oriented away from the roadway were observed to have lower concentrations inside the shelter than outside the shelter. The differences in particulate matter...
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Wei Feng: Impacts of Economic, Technological and Operational Factors on the Economic Competitiveness of Electric Commercial Vehicles in Fleet Replacement Decisions
Electric commercial vehicles (ECV) have the potential to substantially reduce greenhouse gas emissions, noise, and pollution in urban areas. In addition, ECVs have lower per-mile operating costs and potentially lower maintenance costs. However, the initial purchase cost of ECVs is significantly higher than the purchase cost of a conventional diesel vehicle. From a purely economic perspective, there is a cost tradeoff between the low operating and maintenance costs of ECVs and their high initial capital costs. In this paper, a fleet replacement optimization framework is employed to analyze the competitiveness of ECVs. Scenarios with different fleet utilization, fuel efficiency and sensitivity analysis of ten additional factors indicate that ECVs are more cost effective when conventional diesel vehicles’ fuel efficiency is low (8.2 miles/gallon) and daily utilization is more than 54 miles. Breakeven values of some key economic and technological factors that separate the competitiveness between ECVs and conventional diesel vehicles are calculated in all scenarios. For example, in low conventional diesel vehicle fuel efficiency and low daily utilization scenario, ECVs are more competitive when their purchase prices...
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