Vehicle Breakdowns Research Articles

Enhancement of Automatic Incident Detection Algorithms for Singapore's Central Expressway

Timely detection of accidents, vehicle breakdowns, and events that obstruct normal traffic flow is critical to successful implementation of an incident management system in combating traffic congestion along expressways. The purpose of this study is to enhance the performance of existing expressway automatic incident detection algorithms in detecting lane-blocking incidents. In this study, a video-based vehicle detector system was used along the Central Expressway (CTE) in Singapore to collect 160 incidents. Two main tasks were carried out with the CTE incident database to investigate factors that influence incident detection performance and to investigate the use of these findings to enhance existing CTE-calibrated incident detection algorithms. Results indicated that the inclusion of preincident traffic flow or occupancy conditions and the use of traffic speed together with occupancy in an algorithm would yield enhanced detection performance. Of the algorithms studied, the dual variable algorithm, which uses traffic speed and occupancy, can consistently give the best detection performance. From an efficiency perspective, there were no significant changes in time lag in the detection of an incident. A comparative evaluation suggested that the occupancy-based algorithms were generally more effective than the flow-based algorithms in detecting incidents.

Genetic Algorithm-Based Approach for Optimal Location of Transit Repair Vehicles on a Large Urban Network

Determining the optimal location of a fleet of vehicles is necessary in a number of potential applications, such as special repair vehicles for buses on a large public transportation network. The Athens Urban Transport Authority operates a large bus fleet over an extensive network for 19 h a day and serves a population of approximately 4 million people, all in a heavily congested road network. During the 2004 Summer Olympic Games, held in Athens, most spectators, employees, and volunteers were transported to and from Olympic Games venues by public transportation. Dedicated Olympic Games bus lines operated under a tight around-the-clock schedule. During normal operations and particularly during events such as the Olympic Games, incidents such as vehicle breakdowns and minor accidents can have a severe effect on the operation of the public transport network and can cause a significant decrease in the level of service. To help the authority locate bus repair vehicles over the entire network, a decision support system was developed on the basis of an embedded genetic algorithm used for obtaining optimal location solutions. The system's design and performance make it easy to operate under real-time conditions, which is useful for planning and for fast vehicle redeployment.

Fleet scheduling and dispatching for demand-responsive passenger services

This paper describes a software system designed to manage the deployment of a fleet of demand-responsive passenger vehicles such as taxis or variably routed buses. Multiple modes of operation are supported both for the fleet and for individual vehicles. Booking requests can be immediate (i.e. with zero notice) or in advance of travel. An initial implementation is chosen for each incoming request, subject to time-window and other constraints, and with an objective of minimising additional travel time or maximising a surrogate for future fleet capacity. This incremental insertion scheme is supplemented by post-insert improvement procedures, a periodically executed steepest-descent improvement procedure applied to the fleet as a whole, and a “rank-homing” heuristic incorporating information about future patterns of demand. A simple objective for trip-insertion and other scheduling operations is based on localised minimisation of travel time, while an alternative incorporating occupancy ratios has a more strategic orientation. Apart from its scheduling functions, the system includes automated vehicle dispatching procedures designed to achieve a favourable combination of customer service and efficiency of vehicle deployment. Provision is made for a variety of contingencies, including travel slower or faster than expected, unexpected vehicle locations, vehicle breakdowns and trip cancellations. Simulation tests indicate that the improvement procedures yield substantial efficiencies over more naı̈ve scheduling methods and that the system will be effective in real-time applications.

Journey time forecasting for dynamic route guidance systems in incident conditions

New in-vehicle systems for route guidance require optimum routes in a network to be calculated based on current and forecast journey times. Following a brief review of forecasting methods developed for normal traffic conditions, this article describes a new method for the more difficult but particularly important situation of traffic incidents which occur in variety of forms in urban networks, e.g. an accident, a vehicle breakdown, illegal parking/ stopping and so on. In such conditions journey times may be increased not only on the incident link, but also on the links which are the upstream links of the incident location, this could lead to serious congestion, a rise in energy consumption and environmental nuisance. The prediction of the effects of traffic incidents is therefore an important issue for better efficiency and for on-line dynamic route guidance (DRG) systems and other traffic control systems. In this study an incident data base was compiled, based on modelling of several incident/ network/ traffic scenarios using a simulation tool. Generalised statistical models were then developed for predicting the spread of congestion effects following an incident and the required travel time modifications on the incident link and on affected links. The aim was to provide a reasonably robust process for on-line applications, to improve on current ad-hoc methods. The main application of the developed models is in incident management for dynamic route guidance systems particularly in low penetration level (i.e. where the proportion of guided drivers is relatively low).

Modeling Rail Fatigue Behavior with Multiple Hazards

Derailments can be caused by rail fatigue failures, which are of great concern to railroad companies. These companies, therefore, have as an objective to predict the locations and times of potential failures and to perform preventive maintenance. Understanding the relationship between fatigue failures and factors affecting fatigue is essential to estimate when and where rail fatigue failures will occur. This paper presents a statistical rail fatigue model in four stages: 1) the model describes the relationship between probability of failure and usage; 2) the model extends to cases of multiple types of failures; 3) the model is derived for discrete usage categories or time intervals with a continuous spatial representation of rail units; and 4) explanatory variables capturing geometry, maintenance, and material properties are included to explain differences in fatigue behavior among heterogeneous rail units. Using available rail fatigue data, the model is estimated. The modeling framework is useful for other multitype failure behavior and for reliability problems, such as vehicle breakdown.

The Machine Stops: The Breakdown of the Vernian Vehicle

The Machine Stops: The Breakdown of the Vernian Vehicle

The Machine Stops: The Breakdown of the Vernian Vehicle

The Machine Stops: The Breakdown of the Vernian Vehicle

Forecasting transport requirements for district primary health care in Ghana: A simulation study

In rural planning in developing countries, random factors such as vehicle breakdown, weather conditions and staff availability are particularly important. These can be dealt with specially well by simulation. Transportation is also particularly important in rural areas. This paper presents a simulation study of transport requirements for a rural primary health care scheme in Ghana where the random factors are unavailability of vehicles due to repairs and unavailability of health specialists and drivers for work due to holidays, etc. The analysis gives a quick method of calculating the expected number of jobs that can be done for given numbers of vehicles, levels of availability etc. The simulation gives the corresponding probability distribution. The analysis also indicates which random factor has most effect on limiting the number of jobs that can be done. Policy conclusions are drawn regarding the number of vehicles per district and the payment of incentives to staff for good attendance.

Police patrol vehicle breakdowns: The effect on the cost of police service

The results of a simulation of the breakdown of police patrol vehicles in a city of 175,000 population is examined. If a patrol vehicle must be removed from service in order to repair mechanical defects, the quality of police service will not be at the desired (planned) level. In effect, police officers are being paid during a time when they are unable to deliver services—the time during which they are absent from their assigned patrol as a result of the failure of their vehicle. Given the high cost of fielding a police patrol car around the clock, time lost due to mechanical failure can be very costly. The patrol vehicle breakdowns were simulated under several assumptions and for several policies. The magnitude of the implicit cost of lost patrol time due to vehicle breakdowns suggests that investment in a preventive maintenance program may be worthwhile. Furthermore, simple policy changes may result in substantial savings.

A framework for the analysis of the cost of police patrol vehicle breakdowns

A framework for the analysis of the cost of police patrol vehicle breakdowns

The 'Queensway' Mersey Tunnel Entrance Control Project

In 1968, A computer-controlled system was installed by the City of Liverpool to schedule vehicles on the approaches to the Queensway Mersey tunnel. In 1972, the scheme was extended by their own Engineering Division, to provide direct control of the traffic entering the tunnel itself. This paper discusses the project, together with some of the problems encountered in the design of the scheme. Flow measurements have shown an overall increase of about 5 percent, in hourly flows. The success of the scheme is reflected by its smooth operation, even at the peak of commuter flow. A considerable reduction in vehicle breakdowns within the tunnel has been experienced. Air pollution inside the tunnel caused by vehicle exhausts in much less when fluid conditions are maintained, and the fact that traffic is delayed less on the approaches infers that external pollution is also reduced. Additional traffic-sensitivity has been introduced into the computer program to enable the system to react more rapidly to changing conditions, and in the near future, it is hoped to predict approach delays by sampling the flow throughout the tunnel.