October 12, 2017

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Sanjam Singh Article Published in Transportation Research Record

Sanjam Singh (South Carolina) has published an article for the National Academies of Sciences, Engineering, and Medicine Transportation Research Record: Journal of the Transportation Research Board (TRB) Volume 2671, 2017.

Sanjam's article, entitled "Real-World Freeway and Ramp Activity and Emissions for Light-Duty Gasoline Vehicles," was co-authored by Christopher Frey and Maryam Delavarrafiee.  

TRB is one of seven program units of the National Academies of Sciences, Engineering, and Medicine, which provides independent, objective analysis and advice to the nation and conducts other activities to solve complex problems and inform public policy decisions. The Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. TRB's varied activities annually engage more than 7,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest by participating on TRB committees, panels, and task forces. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation.


There are few data on differences in real-world emissions by in-use vehicles when they operate on freeway ramps compared with operations on the freeway itself. The objective of this paper is to quantify the variability in link-based emissions rates for on-ramps and off-ramps in comparison to rates on freeways. Real-world measurements were made with the use of a portable emissions measurement system (PEMS) for selected vehicles, ramps, and freeway segments. The methodology included development of a study design for field data collection of vehicle activity and emissions, execution of the study design, quality assurance of the raw data, and analysis of the quality-assured data. Four light-duty gasoline vehicles were driven on two routes, each composed of on-ramp, freeway, and off-ramp links. Data were collected for morning peak, evening peak, and off-peak time periods. A PEMS test was used to measure exhaust emissions of oxides of nitrogen (NOx), hydrocarbon (HC), and carbon monoxide (CO). The emissions rates for on-ramps were shown to be substantially higher than rates on freeways for NOx, HC, and CO. Some of this variability in emissions rates can be explained by link average vehicle specific power, which can vary by time of day and from one location to another. The variability in emissions rates by route and time of day indicates that there can be complex interactions between traffic flow, road geometry, and emissions rates. Recommendations are offered for additional study and regarding how these results can be used by researchers and practitioners.

More Information

Read the article at: http://trrjournalonline.trb.org/doi/10.3141/2627-03.
Learn more about the Transportation Research Board at: http://www.trb.org/Main/Home.aspx.
For consultation regarding Emissions for Light-Duty Gasoline Vehicles, contact Sanjam Singh at This email address is being protected from spambots. You need JavaScript enabled to view it..
Learn more about Sanjam at: https://www.linkedin.com/in/sanjamsingh/