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- Wang, Xiaoning, et al.
(author)
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Effectiveness of driver's bounded rationality and speed guidance on fuel-saving and emissions-reducing at a signalized intersection
- 2021
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 325, s. 129343-
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Journal article (peer-reviewed)abstract
- To reduce the fuel consumption and emissions of drivers passing through signalized intersections, this research proposes a fuel-saving and emissions-reducing strategy at a signalized intersection which takes into account driver's bounded rationality and speed guidance, including the theoretical basis of strategy, the scenario division of vehicle speed guidance, and the solution of vehicle optimal trajectory. Drivers are divided into three types: aggressive, normal, and conservative. Bounded rationality is divided into three levels: low, medium, and high. And the 3 x 3 x 3 numerical simulation experiments are carried out under low, medium, and high traffic flow. The results show that when the speed guidance is received, aggressive drivers have the greatest fuel-saving and emissions-reducing benefits, followed by conservative drivers. When the bounded rationality level changes under high traffic flow or the level of traffic flow and bounded rationality change concurrently, the benefits will be greatly affected. The driver's bounded rationality harms fuel consumption and emissions, and this negative effect increases with the increase of traffic flow. Providing corrected speed guidance can effectively reduce the negative effect. This study can provide more effective guidance information for drivers in a manual driving environment.
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| 2. |
- Wang, Yuxuan, et al.
(author)
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Are shared electric scooters energy efficient?
- 2021
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In: Communications in Transportation Research. - : Elsevier BV. - 2772-4247. ; 1
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Journal article (peer-reviewed)abstract
- Shared electric scooters (e-scooter) are booming across the world and widely regarded as a sustainable mobility service. An increasing number of studies have investigated the e-scooter trip patterns, safety risks, and environmental impacts, but few considered the energy efficiency of e-scooters. In this research, we collected the operational data of e-scooters from a major provider in Gothenburg to shed light on the energy efficiency performance of e-scooters in real cases. We first develop a multiple logarithmic regression model to examine the energy consumption of single trips and influencing factors. With the regression model, a Monte Carlo simulation framework is proposed to estimate the fleet energy consumption in various scenarios, taking into account both trip-related energy usage and energy loss in idle status. The results indicate that 40% of e-scooter battery energy was wasted in idle status in the current practice, mainly due to the relatively low usage rate (0.83) of e-scooters. If the average usage rate drops below 0.5, the wasted energy could reach up to 53%. In the end, we present a field example to showcase how to optimally integrate public transport with e-scooters from the perspective of energy efficiency. We hope the findings of this study could help understand and resolve the current and future challenges regarding the ever-growing e-scooter services.
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