On-road measurements and modelling of vehicular emissions during traffic interruption and congestion events in an urban traffic corridor
TL;DR: In this paper, the authors investigated the performances of two emission models for estimating emissions from passenger cars and auto-rickshaws of different mileages, moving with a traffic fleet during these events.
About: This article is published in Atmospheric Pollution Research.The article was published on 2019-03-01. It has received 29 citations till now.
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TL;DR: In this paper, the authors evaluated the fuel consumption and the overall gaseous emissions in various road conditions, and the vehicle specific powers (VSPs) with determining the road load coefficients and regression coefficient by multiple linear regression analysis and revealed the fuel use and the emissions per VSP of vehicles in these six different conditions.
35 citations
TL;DR: Overall, emissions decreased from the city centers toward surrounding areas and the higher contributions of heavy-duty trucks meant that higher emissions appeared along highways in a vein-like distribution, providing a theoretical basis for the effective prevention and control of air pollution in the NCP.
27 citations
TL;DR: In this paper, the regulated, particulate, and unregulated emissions, and the fuel economy (FE) from a direct injection spark ignition (DISI) vehicle were investigated on a chassis dynamometer.
24 citations
TL;DR: In this paper, a practical approach comprising of model estimation and real-world measurements is applied to discuss the role of urban development and public culture in the driving behavior and vehicle emissions in an unsustainable urbanized city, i.e. Isfahan, Iran.
13 citations
TL;DR: GWP mitigation was mainly driven by CO, CH4, NOx, VOCs, and partially by CO2, while N2O negatively affected GWP mitigation, which can be used to promote an eco-tourism industry.
Abstract: This study explores the climate impacts of on-road tourist transportation with alternate mitigation strategies. To this end, greenhouse gas (GHG) emissions for 2016 and emissions under four “what-if” scenarios were estimated for a popular tourist site in Pakistan, i.e., Murree Hills, using the international vehicle emissions model. Alternate scenarios included occupancy optimization, bus transit system, and Euro II and Euro IV implementation. The emissions were further decomposed using the log mean Divisia index method to study the drivers of global warming potential (GWP) mitigation. As per the results, the total 20-year GWP for 2016 was equal to 51,262 tons CO2 equivalent, and maximum reduction was achieved under the bus transit system scenario having a 20-year GWP of 25,736 tons CO2 equivalent, i.e., 49.8% reduction. Relative to the base year, GWP reductions were also quite significant for Euro IV (46.8%), Euro II (45.8%), and occupancy optimization (32.3%) scenarios. For the base year, CO2 held a share of 87.3% in total emissions; however, its share in the 20-year GWP was 39.7% indicating its reduced impact on total GWP as compared to N2O, CO, NOx, VOC, and CH4. Based on the decomposition results for alternate scenarios, GWP mitigation was mainly driven by CO, CH4, NOx, VOCs, and partially by CO2, while N2O negatively affected GWP mitigation. These results provide several policy-level instruments for developing countries to design a transition to an eco-friendly tourist transport management system. The policy implications from this study can be used to promote an eco-tourism industry.
12 citations
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Book•
05 Feb 1987
TL;DR: In this paper, the authors present an introduction to automobile aerodynamics, including aerodynamic drag of cars and light vans, and numerical methods for computation of flow around road vehicles, and wind tunnels for automobile aerodynamic testing.
Abstract: Contents: Introduction to automobile aerodynamics. Some fundamentals of fluid mechanics. Performance of cars and light vans. Aerodynamic drag of passenger cars. Driving stability in side winds. Operation, safety and comfort. High performance vehicles. Commercial vehicles. Engine cooling systems. Heating, ventilation and air conditioning of motor vehicles. Wind tunnels for automobile aerodynamics. Measurement and test techniques. Numerical methods for computation of flow around road vehicles.
802 citations
Dissertation•
01 Jan 1999
TL;DR: McRae et al. as mentioned in this paper used a tunable infrared laser differential absorption spectrometer (TILDAS) remote sensor to gather the first on-road measurements of N20 and N02, and the first high precision measurements of NO.
Abstract: Motor vehicles are one of the largest sources of air pollutants worldwide. Despite their importance, motor vehicle emissions are inadequately understood and quantified. This is due in part to large variations in individual vehicle emissions with changing operating conditions, and to significant differences between vehicles. To better relate emissions with operating conditions, a new parameter termed "specific power" (SP) is presented. SP is the instantaneous tractive power per unit vehicle mass. This parameter has three main advantages: it can be calculated from roadside measurements, it captures most of the dependence of light-duty vehicle emissions on driving conditions, and it is directly specified in emissions certification cycles. The dependence of CO, HC, and NOx emissions on SP is better than on several other commonly used parameters, such as speed, acceleration, power, or fuel rate. Using SP as the basic metric allows meaningful comparisons to be made between data from different remote sensing sites, dynamometer driving cycles, and emission models. Modem U.S. vehicles are likely to operate under commanded enrichment when SP exceeds the maximum value on the Federal Test Procedure (-22 kW/Metric Ton). This may allow transient high emissions to be screened out during future remote sensing campaigns. Remote sensing can address the problem of inter-vehicle differences by quickly and cheaply measuring the emissions of large numbers of vehicles. Here, a tunable infrared laser differential absorption spectrometer (TILDAS) remote sensor was used to gather the first on-road measurements of N20 and N02, and the first high precision measurements of NO. NO was detected with a sensitivity of 5 ppm, which allowed even Ultra Low Emission Vehicles to be measured. On-road accuracy was demonstrated by comparing the TILDAS results with the on-board measurements of a heavy-duty diesel truck (HDDT). The remote sensor could operate with an optical path length of 88 meters, more than five times that of competing instruments. The NO and N20 emission distributions of passenger cars (PCs) and light-duty trucks (LDTs) were found to be highly skewed, while the NO emission distribution for HDDTs was not. N20 emissions from PCs and LDTs are estimated to contribute between 0.5% and 0.9% to U.S. greenhouse gas emissions. Thesis supervisor: Gregory J. McRae Title: Bayer Professor of Chemical Engineering
455 citations
TL;DR: A comparative overview of urban transport in the world's two most populous countries: China and India, is provided in this article, where the authors assess government policies in each country and suggest a range of specific improvements.
319 citations
TL;DR: In this article, the authors measured in a road tunnel in Stockholm, Sweden give the real-world traffic emission factors for a number of gaseous and particle pollutants, including 49 different polycyclic aromatic hydrocarbons (PAH), CO, NOX, benzene, toluene, xylenes, aldehydes, elements and inorganic/organic carbon contained in particles, the sub-micrometer aerosol number size distribution, PM2.5 and PM10.
247 citations
TL;DR: The results demonstrate that alternative routing can significantly impact trip emissions and vehicle-specific models are needed to capture episodic effects of emissions for near-road short-term human exposure assessment.
Abstract: The objective here is to quantify the variability in emissions of selected light duty gasoline vehicles by routes, time of day, road grade, and vehicle with a focus on the impact of routes and road grade. Field experiments using a portable emission measurement system were conducted under real-world driving cycles. The study area included two origin/destination pairs, each with three alternative routes. Total emissions varied from trip to trip and from route to route due to variations in average speed and travel time. On an average trip basis, the total NO emissions differed by 24% when comparing alternative routes and by 19% when comparing congested travel time with less congested traffic time. Positive road grades were associated with an approximately 20% increase in localized emissions rates, while negative road grades were associated with a similar relative decrease. The average vehicle-specific power based NO modal emission rates differed by more than 2 orders of magnitude when comparing different vehicles. The results demonstrate that alternative routing can significantly impact trip emissions. Furthermore, road grade should be taken into account for localized emissions estimation. Vehicle-specific models are needed to capture episodic effects of emissions for near-road short-term human exposure assessment.
207 citations