Samuel Labi
4 records found
1
Sustainable Planning of Electric Vehicle Charging Stations
A Bi-Level Optimization Framework for Reducing Vehicular Emissions in Urban Road Networks
This paper proposes a decision-making framework for a multiple-period planning of electric vehicle (EV) charging station development. In this proposed framework, transportation planners seek to implement a phased provision of electric charging stations as well as repurposing gas stations at selected locations. The developed framework is presented as a bi-level optimization problem that determines the optimal electric charging network design while capturing the practical constraints and travelers’ decisions. The upper level minimizes overall vehicle CO emissions by selecting optimal charging stations and their capacities, while the lower-level models travelers’ choices of vehicle class (EV or conventional) and travel routes. A genetic algorithm is developed to solve this problem. The results of the numerical experiments describe the sensitive nature of EV market penetration rates in the urban traffic stream and overall vehicle CO emissions to EV charging station availability and capacity. The findings can assist transportation agencies in designing effective EV charging infrastructure by identifying optimal locations and capacities, as well as in creating policies to encourage EV use over time. This study supports broader efforts to reduce air pollution and promote sustainable transportation by promoting EV adoption in the long term.
@enThe rising demand for electric vehicles (EVs), motivated by their environmental benefits, is generating an increased need for EV charging infrastructure. Also, it has been recognized that the adequacy of such infrastructure helps promote EV use. Therefore, to facilitate EV adoption, governments seek guidance on continued investments in EV charging infrastructure development. Such investment decisions, which include EV charging station locations and capacities, and the timing of such investments require robust estimates of future travel demand and EV battery range constraints. This paper develops and implements a framework to establish an optimal schedule and locations for new charging stations and decommissioning gasoline refueling stations over a long-term planning horizon, considering the uncertainty in future travel demand forecasts and the driving range heterogeneity of EVs. A robust mathematical model is proposed to solve the problem by minimizing not only the worst-case total system travel cost but also the total penalty for unused capacities of charging stations. This study uses an adaptation of the cutting-plane method to solve the proposed model. Based on two key decision criteria (travelers' cost and charging supply sufficiency), the results indicate that the robust scheme outperforms its deterministic counterpart.
@enReduced headways of connected and automated vehicles (CAV) provide opportunities to address traffic congestion and environmental adversities. This benefit can be utilized by deploying CAV-dedicated lanes (CAVDL). This paper presents a bi-level optimization model that captures CAV market size uncertainty. The upper level determines the links (and number of lanes) for CAVDL deployment to minimize emissions. It considers lane reallocation policies that account for the prospect of smaller width of CAV-dedicated lane due to the smaller lateral wander of CAV tire tracks. This can increase the total number of lanes on wide highway sections. At the lower level, equilibrium and demand diffusion models capture travelers’ route and vehicle-type choices. The bi-level model is formulated as a min–max mathematical program with equilibrium conditions and solved using the cutting-plane scheme and active-set algorithm. The computational experiments indicate that the robust plans have superior performance compared to the deterministic plan in pessimistic cases.
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