Reliability Analysis of Public Transit Systems Using Stochastic Simulation Reliability Analysis of Public Transit Systems Using Stochastic Simulation (original) (raw)

Reliability Analysis of Public Transit Systems Using Stochastic Simulation

patrec.org

Unreliable public transport systems cause excessive waiting times, late or early arrivals at destinations and missed connections for passengers. Also, unreliability results in economic losses to transit operators through under utilization of vehicles, equipment and work force. The reliability ...

A simulation-based reliability assessment approach for congested transit network

Journal of Advanced Transportation, 2004

This paper is an attempt to develop a generic simulation-based approach to assess transit service reliability, taking into account interaction between network performance and passengers' route choice behaviour. Three types of reliability, say, system wide travel time reliability, schedule reliability and direct boarding waiting-time reliability are defined from perspectives of the community or transit administration, the operator and passengers. A Monte Carlo simulation approach with a stochastic user equilibrium transit assignment model embedded is proposed to quantify these three reliability measures of transit service. A simple transit network with a bus rapid transit (BRT) corridor is analysed as a case study where the impacts of BRT components on transit service reliability are evaluated preliminarily.

The effects of network structure on reliability of transit service

Transportation Research Part B-methodological, 1980

A set of simulation experiments are described which have been constructed to investigate the effects on service reliability of several characteristics of network 'structure in urban bus systems. Principal focus is on the factors which lead to vehicle bunching, and on the effects of network form and route density on transfers. The results of these experiments highlight the importance of controlling link travel time variability, and of scheduling to ensure expeditious transferring, especially in radial networks.

Bus travel time reliability analysis: a case study

Proceedings of the ICE - Transport, 2014

The travel time reliability of buses has become increasingly important for public transit companies. In this study, a novel approach is proposed to evaluate and analyse the travel time reliability of bus services provided by TransLink in Queensland, Australia. In view of their stochastic features, the two components of travel time – dwell time and driving time – are represented by discrete distributed and normally distributed random variables respectively. Accordingly, the travel time could be described by Gaussian mixture models. Based on the proposed model, impact analysis shows that bus line reliability would increase by around 15% if onboard top-up for ‘go cards' (electronic tickets) was not offered by TransLink. It was found that not providing this top-up method would not significantly harm the benefit of go card users, but it would substantially increase the total social benefit thanks to improved bus line reliability.

Urban Public Transport System's Reliability Estimation Using Microscopic Simulation

Transport and Telecommunication, 2012

In the article the procedure of the reliability measures estimation for one route of the public transport network on the basis of a traffic flow modelling is suggested. A definition of UPTS reliability is based on the analysis of the Travel Time Reliability, Arrival Time Reliability and Probability of arriving to the stops with delay no more than m minutes. The approach is applied to the real task of the reliability estimation for Riga city public transport route. The microscopic model of transport network fragment is used for it.

Reliability Assessment and Improvements along a Bus Corridor

2015

Service reliability is an important indicator of transit performance, and has been the subject of much attention in both the research and practice for decades. Reliability of bus service depends on variations in service characteristics such as travel time, schedule adherence, headway, and wait time. As a fundamental property of bus service, reliability determines services' cost and attractiveness to existing and potential passengers. It is important to the transit agency for resource planning and operation. In this study, two frameworks are developed to assess and improve bus route service reliability. The reliability of a bus route is assessed by measuring variations in service characteristics, and this can be achieved through: 1) selection of performance measures, 2) evaluation of selected measures, and 3) calculation of selected measures. 16 performance measures are selected after conducting a comprehensive literature review, 12 of which are for the assessment of reliability, and 8 for service efficiency. The 16 measures are evaluated with respect to interested party (agency, operator & passenger), service type (high & low frequency service), and analysis level (stop, corridor, route & network). The assessment framework is applied to Route 1 in the City of Edmonton. Historical Route 1 performance data is collected from the Automatic Passenger Counter (APC) database of Edmonton Transit System (ETS). The overall results of estimated measures indicated that a set of performance measures can reflect reliability from every aspect. It was observed that some measures show that Route 1 is reliable, while some indicate unreliability of Route 1. It is also observed that performance of Route 1 during peak periods is worse than off-peak periods. iii A reliability improvement process through bus route scheduling is also introduced. A schedule-based holding strategy was tested, where early buses with slack time are hold at the timing point until scheduled departure time. In this strategy, slack time is determined from a stochastic optimization model, where the objective is to minimize schedule deviation as well as variation in schedule deviation. Slack time is incorporated into the scheduled departure time. Thus, early buses are required to depart at scheduled departure time. Besides schedule-based holding strategy, transit signal priority (TSP) is also used to improve reliability. In this study, the schedule-based holding strategy is also applied to a bus corridor that has TSP. The application of new schedules that incorporate the holding strategy on bus Route

Transit Vehicles' Headway Distribution and Service Irregularity

Public Transport

Pairing, or bunching, of vehicles on a public transportation line influences the adaptive choice at stops due to the random headways and waiting times it determines. In order to ensure consistency with the characteristics of service perturbations, as represented by a transit operation model, it is important to identify the headway distributions representing service perturbations. A stochastic simulation model is developed for a one-way transit line, which accounts for several service characteristics (dwell time at stops, capacity constraint and arrivals during the dwell time). Samples of headways at the main stops are utilized to build histograms of the headway’s frequencies by their length, which allow to identify the functional forms and parameters of the headway distributions. For these stops, density plots of consecutive headways are also produced. Sensitivity analysis is carried out to identify the effect of key parameters (dispatching headway, maximum load and running time).

Definition and Properties of Alternative Bus Service Reliability Measures at the Stop Level

Journal of Public Transportation, 2013

The Transit Capacity and Quality of Service Manual (TCQSM) provides transit agencies with tools for measuring system performance at different levels of operation. Bus service reliability, one of the key performance measures, has become a major concern of both transit operators and users because it significantly affects user experience and service quality perceptions. The objective of this paper is to assess the existing reliability measures proposed by TCQSM and develop new ones at the bus stop level. The latter are not suggested as replacements for the existing measures; rather, they are complementary. Using empirical data from archived Bus Dispatch System (BDS) data in Portland, Oregon, a number of key characteristics of distributions of delay (schedule deviation) and headway deviation are identified. In addition, the proposed reliability measures at the stop level are capable of differentiating between the costs of being early versus late. The results of this study can be implemented in transit operations for use in improving schedules and operations strategies. Also, transit agencies can use the proposed reliability measures to evaluate and prioritize stops for operational improvement purposes.

Bus Travel Time Reliability Incorporating Stop Waiting Time and In-vehicle Travel Time with AVL Data

2022

Improving bus operation quality can attract more commuters to use bus transit, and therefore reduces the share of car and alleviates traffic congestion. One important index of bus operation quality is the bus travel time reliability, which in this paper is defined to be the probability when the sum of bus stop waiting time and in-vehicle travel time is less than a certain threshold. We formulate the bus travel time reliability by the convolution of independent events’ probabilities, and elaborate the calculation method using Automatic Vehicle Location (AVL) data. Next, the No.63 Bus Line in Harbin City is used to test the applicability of the proposed method, and analyze the influence factors of the bus travel time reliability. The numerical results show that factors such as weather, workday, departure time, travel distance, and the distance from the boarding stop to the bus departure station will significantly affect the travel time reliability. At last, some general conclusions an...