Luis Ferreira

PUBLIC TRANSPORTATION ACCESS

The form of a city has a major impact on the lifestyles of its residents. As urban centers grow, careful strategies are required to ensure that the regional quality of life is not adversely affected by this growth. An important strategic consideration is transportation planning. Questions regarding the sustainability of dispersed car dependent urban forms have led to a renewed interest in public transportation. This paper examines access to public transportation and discusses approaches for improving such access. Examples from the South East Queensland region of Australia will be used for illustration.

Heuristic Techniques for Single Line Train Scheduling

Optimising a train schedule on a single line track is known to be NP-Hard with respect to the number of conflicts in the schedule. This makes it difficult to determine optimum solutions to real life problems in reasonable time and raises the need for good heuristic techniques. The heuristics applied and compared in this paper are a local search heuristic with an improved neighbourhood structure, genetic algorithms, tabu search and two hybrid algorithms. When no time constraints are enforced on solution time, the genetic and hybrid algorithms were within five percent of the optimal solution for at least ninety percent of the test problems.

Measuring driver responses at railway level crossings

Railway level crossings are amongst the most complex of road safety control systems, due to the conflicts between road vehicles and rail infrastructure, trains and train operations. Driver behaviour at railway crossings is the major collision factor. The main objective of the present paper was to evaluate the existing conventional warning devices in relation to driver behaviour. The common conventional warning devices in Australia are a stop sign (passive), flashing lights and a half boom-barrier with flashing lights (active). The data were collected using two approaches, namely: field video recordings at selected sites and a driving simulator in a laboratory. This paper describes and compares the driver response results from both the field survey and the driving simulator. The conclusion drawn is that different types of warning systems resulted in varying driver responses at crossings. The results showed that on average driver responses to passive crossings were poor when compared to active ones. The field results were consistent with the simulator results for the existing conventional warning devices and hence they may be used to calibrate the simulator for further evaluation of alternative warning systems.

Optimizing the Location of Intermodal Freight Hubs: An Overview of Agent Based Modelling Approach

This paper aims at developing an integral model for the evaluation of road-rail intermodal freight hub location decisions. The model comprises four dominant agents, namely, hub owners or operators; transport network infrastructure providers; hub users; and communities. An agent based modelling approach is introduced to allow such negotiation to happen to achieve a global objective. The paper outlines the methodology to be used. It also presents an initial location selection process, a testing with individual objective functions, and a design for an agent based model using a case study of intermodal freight hub location decisions in South East Queensland of Australia.

Hazard based models for freeway traffic incident duration

Assessing and prioritising cost-effective strategies to mitigate the impacts of traffic incidents and accidents on non-recurrent congestion on major roads represents a significant challenge for road network managers. This research examines the influence of numerous factors associated with incidents of various types on their duration. It presents a comprehensive traffic incident data mining and analysis by developing an incident duration model based on twelve months of incident data obtained from the Australian freeway network. Parametric accelerated failure time (AFT) survival models of incident duration were developed, including log-logistic, lognormal, and Weibul-considering both fixed and random parameters, as well as a Weibull model with gamma heterogeneity. The Weibull AFT models with random parameters were appropriate for modelling incident duration arising from crashes and hazards. A Weibull model with gamma heterogeneity was most suitable for modelling incident duration of stationary vehicles. Significant variables affecting incident duration include characteristics of the incidents (severity, type, towing requirements, etc.), and location, time of day, and traffic characteristics of the incident. Moreover, the findings reveal no significant effects of infrastructure and weather on incident duration. A significant and unique contribution of this paper is that the durations of each type of incident are uniquely different and respond to different factors. The results of this study are useful for traffic incident management agencies to implement strategies to reduce incident duration, leading to reduced congestion, secondary incidents, and the associated human and economic losses.

Transit Users’ Route‐Choice Modelling in Transit Assignment: A Review

Abstract This paper reviews the main studies on transit users’ route choice in the context of transit assignment. The studies are categorized into three groups: static transit assignment, within‐day dynamic transit assignment, and emerging approaches. The motivations and behavioural assumptions of these approaches are re‐examined. The first group includes shortest‐path heuristics in all‐or‐nothing assignment, random utility maximization route‐choice models in stochastic assignment, and user equilibrium based assignment. The second group covers within‐day dynamics in transit users’ route choice, transit network formulations, and dynamic transit assignment. The third group introduces the emerging studies on behavioural complexities, day‐to‐day dynamics, and real‐time dynamics in transit users’ route choice. Future research directions are also discussed.

Modelling the number and location of sidings on a single line railway

Abstract This article puts forward a model to determine the required number and position of sidings on a single track rail corridor. The sidings are positioned to minimise both the risk of delays and the delays caused by train conflicts, for a given cyclic train schedule. The key feature of the model is the allowance of variable train velocities and non-uniform departure times. A decomposition procedure, used to partition the mixed integer non-linear program into easily solvable sub-models was found to converge quickly. Numerical results, using actual train schedules, indicate considerable savings in terms of both conflict delay and risk of delay when track sidings are positioned using the model. Simulations are used to demonstrate how the model can be used determine the required number of sidings given a pre-defined level of service.

Modelling delay risks associated with train schedules

The overall timetable reliability is a measure of the likely performance of the timetable as a whole, in terms of schedule adherence. The reliability of arrivals is a critical performance measure for all rail markets. This paper presents analytically based models designed to quantify the amount of delay risk associated with each track segment, train and the schedule as a whole. Three main types of delays are modelled, namely: terminal/station delays; track related delays; and rolling stock related delays. The models can be used to prioritise investment projects designed to improve timetable reliability. For example, a comparison can be made between track, terminal and rolling stock projects, in terms of their likely impact on timetable reliability. The effect of timetable changes on likely reliability can also be modelled. Using the risk models developed here, it is possible to assess the likely effect of removing/adding sidings for passing and crossing purposes, under single line train operations. The paper illustrates the use of the models using a series of tests with a timetable consisting of nine trains and six stations. The effect of changing assumptions regarding delays due to terminal congestion; track related problems; and rolling stock, are modelled and the results are summarised. Also modelled is the impact of changes to the timetable.

Influence of Platform Walking on BRT Station Bus Dwell Time Estimation: Australian Analysis

The common approach to estimate bus dwell time at a Bus Rapid Transit (BRT) station platform is to apply the traditional dwell-time methodology derived for suburban bus stops. Current dwell-time models are sensitive toward bus type and fare collection policy along with the number of boarding and alighting passengers. However, they fall short in accounting for the effects of passengers walking on a relatively longer BRT station platform. Analysis presented in this paper shows that the average walking time of a passenger at a BRT platform is 10 times more than that of a bus stop. The requirement of walking to the bus entry door at the BRT station platform may lead to the bus experiencing a higher dwell time. This paper presents a theory for a BRT network that explains the loss of station capacity during peak period operation. It also highlights shortcomings of present available bus dwell-time models suggested for the analysis of BRT operation.

Optimal burn-in time under cumulative free replacement warranty

Abstract In this paper, optimal burn-in time to minimize the total mean cost, which is the sum of manufacturing cost with burn-in and cumulative warranty-related cost, is studied. When the products with cumulative warranty have high failure rate in the early period (infant mortality period), burn-in procedure is considered to eliminate the early product failures. After burn-in, the posterior product life distribution and the cumulative warranty-related cost are dependent on burn-in time; long burn-in period decreases the warranty-related cost, but it increases the manufacturing cost. The paper provides a methodology to obtain the total mean cost under burn-in and cumulative warranty. Properties of the optimal burn-in time are analyzed here. Numerical examples and sensitivity analysis are used to demonstrate the applicability of the methodology derived in the paper.