This can help researchers, traffic planners or practitioners to reduce congestion and emissions, and enhance road traffic management near urban areas.read more read lessĪbstract: The purpose of this study is to assess the effects on air pollution that may derive from replacing a signal-controlled intersection with a roundabout, using a before-and-after approach. The proposed methodology can be used to quantify the performance of roundabout layouts in suburban areas by simply identifying their traffic volumes, noise level, pollutant emission and representative speed profiles. CTL was the worst option in terms of both CO2 and nitrogen oxides (NOx). Although SL yielded the lowest carbon dioxide (CO2) per vehicle, a high equivalent continuous A-weighted sound level (LAeq) was returned because vehicles drove at moderate speeds in the approach and low conflicting traffic was identified when compared to the other layouts. Afterwards, predictive discrete choice models that correlate the probability of occurrence of speed profiles (no stop, stop once and multiple stops) with roundabout operational parameters were developed. Field measurements were carried out with a light duty vehicle in single-lane (SL), compact two-lane (CTL) and multi-lane (ML) roundabouts using Portable Emission Measurements Systems, On-Board Diagnostic scan tool and Sound Level Meter, to measure real-world exhaust emissions, engine activity and acoustic data, respectively. This research compares different suburban roundabouts in terms of traffic performance, pollutant and noise emissions through an integrated empirical assessment. The obtained results of emission calculations on roundabouts may be used to identify areas of increased emission of harmful exhaust components, as well as an introduction to prepare new roundabout design guidelines concerning emission data.read more read lessĪbstract: Increasing concern about global warming and air quality has meant an increasing use of energetic and environmental indicators in roundabout design. Statistical analysis of the received boosted regression tree models based on the coefficient of regression, root mean square error, and mean absolute error and based on the visual assessment of the results show that the obtained models are well represented by real data. Due to the specific traffic conditions that prevail at the roundabout (acceleration, braking, acceleration to a certain speed), the methodology for creating an exhaust emission model for this type of objects has been proposed. The results show that in the range of roundabouts, there is an increased emission of harmful exhaust components, such as CO2, THC, CO, and NOx. This paper presents an analysis of emission data from the PEMS system for real driving cycles of various types of vehicles, complying with EURO2-EURO6 standards, fueled with petrol, LPG, and diesel in urban, rural, and motorway areas as well as detailing roundabouts. The development of systems for measuring emissions of exhaust gases caused the exit from stationary chassis dynamometers to real road test. Abstract: Road transport is the main source of pollution to the environment in urban areas therefore, there is a need to accurately estimate the amount of exhaust gases emitted by motor vehicles.
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