@article{rasdorf_frey_lewis_kim_pang_abolhassani_2010, title={Field Procedures for Real-World Measurements of Emissions from Diesel Construction Vehicles}, volume={16}, ISSN={["1943-555X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-78649383748&partnerID=MN8TOARS}, DOI={10.1061/(asce)is.1943-555x.0000027}, abstractNote={Construction vehicles are a source of nonroad mobile air pollutant emissions. Emissions from construction vehicles are typically quantified based on steady-state modal engine dynamometer tests using uninstalled stationary engines. However, these tests do not represent real-world activity. Therefore, there is a need to quantify energy use and air pollutant emissions from construction vehicles based on in-use measurement methods. The purpose of this paper is to outline standard procedures for field data collection for construction vehicles. This methodology is based on second-by-second measurement of in-use activity and air pollutant emissions using a portable emissions measurement system. The field data collection methodology includes the development of a study design, installation and use of instrumentation, and field measurements. After the field data collection, the raw data undergo a quality assurance procedure to check for and correct the synchronization between the engine data and emission data. This procedure also identifies missing data and removes incorrect data. The most significant challenges to data collection include suitable weather, difficult operating conditions, and scheduling data collection sessions. Sample real-world data measurement results for a rubber tire loader are presented. The work presented here can be used as a foundational example for conducting other data collection efforts and analysis of construction vehicle emissions.}, number={3}, journal={JOURNAL OF INFRASTRUCTURE SYSTEMS}, author={Rasdorf, William and Frey, Christopher and Lewis, Phil and Kim, Kangwook and Pang, Shih-Hao and Abolhassani, Saeed}, year={2010}, month={Sep}, pages={216–225} }
 @article{pang_frey_rasdorf_2009, title={Life cycle inventory energy consumption and emissions for biodiesel versus petroleum diesel fueled construction vehicles}, volume={43}, DOI={10.1021/os802916u}, number={16}, journal={Environmental Science & Technology}, author={Pang, S. H. and Frey, H. Christopher and Rasdorf, W. J.}, year={2009}, pages={6398–6405} }
 @article{lewis_rasdorf_frey_pang_kim_2009, title={Requirements and Incentives for Reducing Construction Vehicle Emissions and Comparison of Nonroad Diesel Engine Emissions Data Sources}, volume={135}, ISSN={["0733-9364"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-65249158552&partnerID=MN8TOARS}, DOI={10.1061/(ASCE)CO.1943-7862.0000008}, abstractNote={Nonroad construction vehicles and equipment powered by diesel engines contribute to mobile source air pollution. The engines of this equipment emit significant amounts of carbon monoxide, hydrocarbons, nitrogen oxides, and particulate matter. These pollutants pose serious problems for human health and the environment. Therefore, it is necessary to regulate and control the levels of these pollutants. Furthermore, there are emerging requirements and incentives for “greening” of construction vehicle fleets and operations. Currently, there are two types of standards that regulate air pollution for these types of vehicles: technological standards for engines and quality standards for air. It is also necessary to quantify the levels of emissions that nonroad construction vehicles and equipment produce. Quantification may be based on existing data sources (such as the EPA NONROAD model) or by collecting data directly from the vehicles as they work in the field. The purpose of this paper is to introduce the challenges to quantification of emissions from nonroad construction vehicles, describe associated governmental regulations and incentives for reducing emissions, identify and compare various sources of emissions data, establish the need to collect additional data, and propose a future research agenda that focuses on air pollution generated by construction vehicles.}, number={5}, journal={JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT-ASCE}, author={Lewis, Phil and Rasdorf, William and Frey, H. Christopher and Pang, Shih-Hao and Kim, Kangwook}, year={2009}, month={May}, pages={341–351} }
 @article{frey_kim_pang_rasdorf_lewis_2008, title={Characterization of Real-World Activity, Fuel Use, and Emissions for Selected Motor Graders Fueled with Petroleum Diesel and B20 Biodiesel}, volume={58}, ISSN={["1047-3289"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-55049085635&partnerID=MN8TOARS}, DOI={10.3155/1047-3289.58.10.1274}, abstractNote={Motor graders are a common type of nonroad vehicle used in many road construction and maintenance applications. In-use activity, fuel use, and emissions were measured for six selected motor graders using a portable emission measurement system. Each motor grader was tested with petroleum diesel and B20 biodiesel. Duty cycles were quantified in terms of the empirical cumulative distribution function of manifold absolute pressure (MAP), which is an indicator of engine load. The motor graders were operated under normal duty cycles for road maintenance and repair at various locations in Wake and Nash Counties in North Carolina. Approximately 3 hr of quality-assured, second-by-second data were obtained during each test. An empirical modal-based model of vehicle fuel use and emissions was developed, based on stratifying the data with respect to ranges of normalized MAP, to enable comparisons between duty cycles, motor graders, and fuels. Time-based emission factors were found to increase monotonically with MAP. Fuel-based emission factors were mainly sensitive to differences between idle and non-idle engine operation. Cycle average emission factors were estimated for road "resurfacing," "roading," and "shouldering" activities. On average, the use of B20 instead of petroleum diesel leads to a negligible decrease of 1.6% in nitric oxide emission rate, and decreases of 19-22% in emission rates of carbon monoxide, hydrocarbons, and particulate matter. Emission rates decrease significantly when comparing newer engine tier vehicles to older ones. Significant reductions in tailpipe emissions accrue especially from the use of B20 and adoption of newer vehicles.}, number={10}, journal={JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION}, author={Frey, H. Christopher and Kim, Kangwook and Pang, Shih-Hao and Rasdorf, William J. and Lewis, Phil}, year={2008}, month={Oct}, pages={1274–1287} }