scholarly journals An Analytical Model for the Many-to-One Demand Responsive Transit Systems

2019 ◽  
Vol 12 (1) ◽  
pp. 298 ◽  
Author(s):  
Di Huang ◽  
Weiping Tong ◽  
Lumeng Wang ◽  
Xun Yang
Keyword(s):  
Analytical Model ◽  
Operating Cost ◽  
Agency Cost ◽  
Continuum Approximation ◽  
Approximation Technique ◽  
User Cost ◽  
Transit System ◽  
User Costs ◽  
The Many ◽  
Demand Responsive Transit

The demand-responsive transit (DRT) service is an emerging and flexible transit mode to enhance the mobility of the urban transit system by providing personalized services. Passengers can make advanced appointments through smartphone applications. In this paper, an analytical model is proposed for the many-to-one DRT system. The agency and user costs are approximated by closed-form expressions. The agency cost, which is also the operation cost, is approximated by the continuum approximation technique. A nearest-neighbor routing strategy is applied, whereby the vehicle always collects the nearest passenger waiting in the system. The Vickrey queueing theory is adopted as the basis for approximating each component of the user cost, which is composed of the out-of-vehicle and in-vehicle waiting times and schedule deviations, which also depend on the service quality of the DRT system. The results of the numerical experiment show that (1) the agency and user costs are influenced significantly by the demand density, and (2) the DRT operator cannot further decrease the operating cost by solely deploying larger vehicles.

Systematic Procedures for the Analysis of Agency and User Costs of Bridge Repair Actions

2018 ◽  
Vol 2672 (12) ◽  
pp. 116-126
Author(s):  
Ehsan Fereshtehnejad ◽  
Jieun Hur ◽  
Abdollah Shafieezadeh ◽  
Mike Brokaw ◽  
Brad Noll ◽  
...  
Keyword(s):  
Cost Estimation ◽  
Cost Effective ◽  
Agency Cost ◽  
User Cost ◽  
Bridge Management ◽  
User Costs ◽  
Vehicle Operation ◽  
Traffic Delays ◽  
Implementation Costs ◽  
The Cost

A primary goal of bridge management systems is to identify maintenance, repair, and replacement (MR&R) strategies that maximize benefits and minimize losses, often expressed in terms of cost. A major factor that greatly impacts outcomes of these frameworks, that is, the most appropriate MR&R strategies, is the cost of implementation and associated consequences of performing such actions. Given that the inventory of bridges maintained by a state department of transportation (DOT) is significantly large, this study is aimed at developing a systematic procedure to reliably estimate the costs through effective utilization of DOTs’ databases. The considered costs include agency cost of administration, engineering, and mobilization; agency direct cost of performing MR&R actions; agency cost of maintenance of traffic; and user cost incurred from traffic delays, vehicle operation, and excess emissions. The study develops a set of models to estimate the duration of various MR&R work plans. These models are subsequently used to propose analytical formulations and algorithms for the estimation of the above costs. The proposed procedures are employed to estimate the agency and user costs associated with a series of light to extensive repair actions for three bridges in Ohio. Independent calculation of some of these costs by Ohio DOT engineers indicated good agreement with results obtained from the proposed systematic methods. The verified procedures for cost estimation developed in this study enable state DOTs and other entities to reliably estimate implementation costs of actions for their large inventory of bridges and identify the most cost-effective MR&R strategies and work plans.

Continuous Approximation Model for Hybrid Flexible Transit Systems with Low Demand Density

2021 ◽  
pp. 036119812199713
Author(s):  
Charalampos Sipetas ◽  
Eric J. Gonzales
Keyword(s):  
Agency Cost ◽  
Optimization Techniques ◽  
Optimization Process ◽  
Analytical Models ◽  
Continuous Approximation ◽  
Flexible Systems ◽  
Transit System ◽  
Transit Systems ◽  
Approximation Techniques ◽  
Service Areas

Flexible transit systems are a way to address challenges associated with conventional fixed route and fully demand responsive systems. Existing studies indicate that such systems are often planned and designed without established guidelines, and optimization techniques are rarely implemented on actual flexible systems. This study presents a hybrid transit system where the degree of flexibility can vary from a fixed route service (with no flexibility) to a fully flexible transit system. Such a system is expected to be beneficial in areas where the best transit solution lies between the fixed route and fully flexible systems. Continuous approximation techniques are implemented to model and optimize the stop spacing on a fixed route corridor, as well as the boundaries of the flexible region in a corridor. Both user and agency costs are considered in the optimization process. A numerical analysis compares various service areas and demand densities using input variables with magnitudes similar to those of real-world case studies. Sensitivity analysis is performed for service headway, percent of demand served curb-to-curb, and user and agency cost weights in the optimization process. The analytical models are evaluated through simulations. The hybrid system proposed here achieves estimated user benefits of up to 35% when compared with fixed route systems, under different case scenarios. Flexible systems are particularly beneficial for serving corridors with low or uncertain demand. This provides value for corridors with low demand density as well as communities in which transit ridership has dropped significantly because of the COVID-19 pandemic.

scholarly journals Optimization Model for Reserve Fleet Sizes in Traditional Transit Systems considering the Risk of Vehicle Breakdowns

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Bowen Hou ◽  
Shuzhi Zhao ◽  
Huasheng Liu ◽  
Jin Li
Keyword(s):  
Optimization Model ◽  
Queueing Theory ◽  
Solution Method ◽  
Transit System ◽  
Transit Systems ◽  
Total Cost ◽  
User Costs ◽  
Transit Services ◽  
Optimized Model ◽  
In Transit

Traditional transit systems are susceptible to unexpected costs and delays due to unforeseen events, such as vehicle breakdowns. The randomness of these events gives the appearance of an imbalance in the number of operating vehicles and of unreliable transit services. Therefore, this paper proposes the queueing theory as a means to characterize the state of any given transit system considering the risk of vehicle breakdowns. In addition, the proposed method is used to create an optimized model for reserve fleet sizes in transit systems, in order to ensure the reliability of the transit system and minimize the total cost of any transit system exposed to the risks of vehicle breakdowns. The optimization is conducted based on the two main characteristics of all bus systems, namely, operator costs and user costs, in both normal and disruptive situations. In addition, the situations in our optimization are generated in scenarios that have a certain degree of probability of experiencing delays. This paper formulates such an optimization model, presents the formulation solution method, and proves the validity of the proposed method.

USER COSTS, THE FINANCIAL FIRM, AND MONETARY AND REGULATORY POLICY

2019 ◽  
Vol 24 (6) ◽  
pp. 1547-1573
Author(s):  
Maksim Isakin ◽  
Apostolos Serletis
Keyword(s):  
Financial Services ◽  
Deposit Insurance ◽  
Banking Sector ◽  
Financial Regulation ◽  
Policy Instruments ◽  
Commercial Banking ◽  
User Cost ◽  
Holding Costs ◽  
User Costs ◽  
Financial Firm

We investigate how key monetary policy instruments and financial regulation affect the banking firm. We take the user-cost approach to the construction of prices for financial services and use quarterly data on the U.S. commercial banking sector, over the period from 1992 to 2016, obtained from the Federal Deposit Insurance Corporation. We use the symmetric generalized Barnett variable profit function to derive demands for and supplies of monetary and nonmonetary goods and provide evidence consistent with neoclassical microeconomic theory. We find that the compensated price elasticities of banking technology are small in magnitude. Yet a hypothetical policy experiment shows that even small changes in the holding costs of financial goods can result in significant changes in user costs and the quantities demanded and supplied.

Using Deficit Function to Determine the Minimum Fleet Size of an Autonomous Modular Public Transit System

2020 ◽  
Vol 2674 (11) ◽  
pp. 532-541 ◽  
Author(s):  
Tao Liu ◽  
Avishai (Avi) Ceder ◽  
Andreas Rau
Keyword(s):  
Autonomous Vehicles ◽  
Large Scale ◽  
Public Transit ◽  
Programming Model ◽  
Real Life ◽  
Single Line ◽  
Continuum Approximation ◽  
Transit System ◽  
Fleet Size ◽  
Minimum Number

Emerging technologies, such as connected and autonomous vehicles, electric vehicles, and information and communication, are surrounding us at an ever-increasing pace, which, together with the concept of shared mobility, have great potential to transform existing public transit (PT) systems into far more user-oriented, system-optimal, smart, and sustainable new PT systems with increased service connectivity, synchronization, and better, more satisfactory user experiences. This work analyses such a new PT system comprised of autonomous modular PT (AMPT) vehicles. In this analysis, one of the most challenging tasks is to accurately estimate the minimum number of vehicle modules, that is, its minimum fleet size (MFS), required to perform a set of scheduled services. The solution of the MFS problem of a single-line AMPT system is based on a graphical method, adapted from the deficit function (DF) theory. The traditional DF model has been extended to accommodate the definitions of an AMPT system. Some numerical examples are provided to illustrate the mathematical formulations. The limitations of traditional continuum approximation models and the equivalence between the extended DF model and an integer programming model are also provided. The extended DF model was applied, as a case study, to a single line of an AMPT system, the dynamic autonomous road transit (DART) system in Singapore. The results show that the extended DF model is effective in solving the MFS problem and has the potential to be applied to solving real-life MFS problems of large-scale, multi-line and multi-terminal AMPT systems.

Work Zone Optimization for Two-Lane Highway Resurfacing Projects with an Alternate Route

2005 ◽  
Vol 1911 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Chun-Hung (Peter) Chen ◽  
Paul Schonfeld ◽  
Jawad Paracha
Keyword(s):  
Simulated Annealing ◽  
Traffic Management ◽  
Agency Cost ◽  
Work Zone ◽  
Time Dependent ◽  
User Cost ◽  
Total Cost ◽  
Management Plans ◽  
Delay Cost ◽  
Alternate Routes

Pavements on two-lane two-way highways are usually resurfaced by closing one lane at a time. Vehicles then travel in the remaining lane along the work zone, alternating directions within each control cycle. In an earlier work, Chen and Schonfeld developed a work zone optimization model for two-lane highways with time-dependent inflows and no detours, based on simulated annealing. In this paper, several alternatives are evaluated, defined by the number of closed lanes and fractions of traffic diverted to alternate routes. The algorithm referred to as SAUASD (simulated annealing for uniform alternatives with a single detour) is developed to find the best single alternative within a resurfacing project. The algorithm referred to as SAMASD (simulated annealing for mixed alternatives with a single detour) is developed to search through possible mixed alternatives and their diverted fractions, to minimize total cost, further including agency cost (resurfacing cost and idling cost) and user cost (user delay cost and accident cost). Thus, traffic management plans are developed with uniform or mixed alternatives within a two-lane highway resurfacing project.

scholarly journals Bridge Management Strategy Based on Extreme User Costs for Bridge Network Condition

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Ladislaus Lwambuka ◽  
Primus V. Mtenga
Keyword(s):  
Multiobjective Optimization ◽  
Traffic Flow ◽  
Developed Countries ◽  
Optimization Approach ◽  
User Cost ◽  
Bridge Management ◽  
User Costs ◽  
First Case ◽  
Conflicting Objectives ◽  
Alternative Routes

This paper presents a practical approach for prioritization of bridge maintenance within a given bridge network. The maintenance prioritization is formulated as a multiobjective optimization problem where the simultaneous satisfaction of several conflicting objectives includes minimization of maintenance costs, maximization of bridge deck condition, and minimization of traffic disruption and associated user costs. The prevalence of user cost during maintenance period is twofold; the first case refers to the period of dry season where normally the traffic flow is diverted to alternative routes usually resurfaced to regain traffic access. The second prevalence refers to the absence of alternative routes which is often the case in the least developed countries; in this case the user cost referred to results from the waiting time while the traffic flow is put on hold awaiting accomplishment of the maintenance activity. This paper deals with the second scenario of traffic closure in the absence of alternative diversion routes which in essence results in extreme user cost. The paper shows that the multiobjective optimization approach remains valid for extreme cases of user costs in the absence of detour roads as often is the scenario in countries with extreme poor road infrastructure.

A simulation study of demand responsive transit system design

2008 ◽  
Vol 42 (4) ◽  
pp. 718-737 ◽  
Author(s):  
Luca Quadrifoglio ◽  
Maged M. Dessouky ◽  
Fernando Ordóñez
Keyword(s):  
System Design ◽  
Simulation Study ◽  
Transit System ◽  
Demand Responsive Transit

scholarly journals User Costs versus Waiting Services and Depreciation in a Model of Production

2010 ◽  
Vol 230 (6) ◽  
Author(s):  
W.Erwin Diewert
Keyword(s):  
Capital Stock ◽  
General Model ◽  
Cost Of Capital ◽  
User Cost ◽  
Capital Goods ◽  
User Costs ◽  
Resource Requirements ◽  
The One ◽  
Investment Goods ◽  
Period Model

SummaryThe paper develops an extension of a one period model of production involving beginning and end of the period capital stocks along with output and input flows that is due to Hicks and Edwards and Bell. This generalized Austrian model of production takes into account that end of the period capital stocks result from: (i) purchases of new investment goods; (ii) internal construction of firm capital stock components and (iii) holdings of (depreciated) capital goods that were held by the firm at the beginning of the period. These different methods of creating end of period holdings of capital stocks generally have different resource requirements and hence the one period production possibilities set is more complex than the usual one. This general model of production is used to justify the decomposition of the Jorgensonian user cost of capital into separate waiting services and depreciation components.

scholarly journals A Threshold Policy for Dispatching Vehicles in Demand-responsive Transit Systems

2019 ◽  
Vol 31 (4) ◽  
pp. 387-395
Author(s):  
Nikola Marković ◽  
Myungseob (Edward) Kim ◽  
Eungcheol Kim ◽  
Sanjin Milinković
Keyword(s):  
Optimal Threshold ◽  
Time Varying ◽  
Threshold Policy ◽  
Transit System ◽  
Travel Mode ◽  
Transit Systems ◽  
Fleet Size ◽  
Vehicle Dispatching ◽  
Simulation Based ◽  
Demand Responsive Transit

This paper considers vehicle dispatching for a flexible transit system providing doorstep services from a terminal. The problem is tackled with an easy-to-implement threshold policy, where an available vehicle is dispatched when the number of boarded passengers reaches or exceeds a certain threshold. A simulation-based approach is applied to find the threshold that minimizes the expected system-wide cost. Results show that the optimal threshold is a function of demand, which is commonly stochastic and time-varying. Consequently, the dispatching threshold should be adjusted for different times of the day. In addition, the simulation-based approach is used to simultaneously adjust dispatching threshold and fleet size. The proposed approach is the first work to analyse threshold dispatching policy. It could be used to help improve efficiency of flexible transit systems, and thereby make this sustainable travel mode more economical and appealing to users.

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