Fleet-Size Model for Light Rail and Bus Rapid Transit Systems

Author(s):  
Lo Rosa Hsu ◽  
Jer-Wei Wu
Author(s):  
Eric Bruun

A parametric cost model was developed to provide both average and marginal cost estimates and to compare annual operating costs for light rail transit (LRT) and bus rapid transit (BRT) under an assumption of additional peak service on weekdays. The model uses readily available data from the U.S. National Transit Database. For illustrative purposes, it is applied to a hypothetical service network simulating universal coverage of a medium-sized metropolitan area with either LRT or BRT operating on trunk lines. The Dallas [Texas] Area Rapid Transit agency is selected for a computational example because it has representative, contemporary performance statistics for both LRT and bus. High and low operating cost estimates based on articulated buses were used for BRT because of a lack of an operational history. For an agency with a similar cost structure to the Dallas agency, both BRT and LRT have lower operating costs on a per space kilometer basis during base periods than do regular buses. Both LRT and the lower BRT cost estimates are comparable for adding service during peak periods. With the higher cost estimate, peak BRT costs 24% more than LRT. For trunk line capacities below about 1,600 spaces per hour, the headway-versus-cost trade-off favors BRT. Above 2,000 spaces per hour, BRT headways become so short that traffic signal priority may not be effective and revenue speed may decrease. The marginal cost of adding off-peak BRT service is substantially less than the average cost of regular buses, and the cost of LRT is even less. Peak fleet size seems to be an important driver of costs. Research methods to verify this are suggested.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2550
Author(s):  
Andrés E. Díez ◽  
Mauricio Restrepo

This paper presents an electrical infrastructure planning method for transit systems that operate with partially grid-connected vehicles incorporating on-board batteries. First, the state-of-the-art of electric transit systems that combine grid-connected and battery-based operation is briefly described. Second, the benefits of combining a grid connection and battery supply in Bus Rapid Transit (BRT) systems are introduced. Finally, the planning method is explained and tested in a BRT route in Medellin, Colombia, using computational simulations in combination with real operational data from electric buses that are currently operating in this transit line. Unlike other methods and approaches for Battery Electric Bus (BEB) infrastructure planning, the proposed technique is system-focused, rather than solely limited to the vehicles. The objective of the technique, from the vehicle’s side, is to assist the planner in the correct sizing of batteries and power train capacity, whereas from the system side the goal is to locate and size the route sections to be electrified. These decision variables are calculated with the objective of minimizing the installed battery and achieve minimum Medium Voltage (MV) network requirements, while meeting all technical and reliability conditions. The method proved to be useful to find a minimum feasible cost solution for partially electrifying a BRT line with In-motion Charging (IMC) technology.


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