Journal of Advanced Transportation

Railway scheduling and timetabling are common stages in the classical hierarchical railway planning process and they perhaps represent the step with major influence on user's perception about quality of service. This aspect, in conjunction with their contribution to service profitability, makes them a widely studied topic in the literature, where nowadays many efforts are focused on improving the solving methods of the corresponding optimization problems. However, literature about models considering detailed descriptions of passenger demand is sparse. This paper tackles the problem of timetable determination by means of building and solving a non-linear integer programming model which fits the arrival and departure train times to a dynamic behavior of demand. The optimization model results are then used for computing several measures to characterize the quality of the obtained timetables considering jointly both user and company points of view. Some aspects are discussed, including the influence of train capacity and the validity of Random Incidence Theorem. An application to the C5 line of Madrid rapid transit system is presented. Different measures are analyzed in order to improve the insight into the proposed model and analyze in advance the influence of different objectives on the resulting timetable.

Data Envelopment Analysis (DEA) has become an established approach for analyzing and comparing efficiency results of corporate organizations or economic agents. It has also found wide application in comparative studies on airport efficiency. The standard DEA approach to comparative airport efficiency analysis has two feeble elements, viz. a methodological and a substantive weakness. The methodological weakness originates from the choice of uniform efficiency improvement assessment, while the substantive weakness in airport efficiency analysis concerns the insufficient attention for short-term and long-term adjustment possibilities in the production inputs determining airport efficiency. The present paper aims to address both flaws by: (i) designing a data-instigated Distance Friction Minimization (DFM) model as a generalization of the standard Banker-Charnes-Cooper (BCC) model with a view to the development of a more appropriate efficiency improvement projection model in the BCC version of DEA; (ii) including as factor inputs also lumpy or rigid factors that are characterized by short-term indivisibility or inertia (and hence not suitable for short-run flexible adjustment in new efficiency stages), as is the case for runways of airports. This so-called fixed factor (FF) case will be included in the DFM submodel of DEA. This extended DEA – with a DFM and an FF component – will be applied to a comparative performance analysis of several major airports in Europe. Finally, our comparative study on airport efficiency analysis will be extended by incorporating also the added value of the presence of shopping facilities at airports for their relative economic performance.

The classical network configuration introduced by Braess in 1968 is of fundamental significance because Valiant and Roughgarden showed in 2006 that `the "global" behaviour of an equilibrium flow in a large random network is similar to that in Braess' original four-node example'. In this paper, a natural generalisation of Braess' network is introduced and conditions for the occurrence of Braess' paradox are formulated for the generalised network. The Braess' paradox has been studied mainly in the context of the classical problem introduced by Braess and his colleagues, assuming a certain type of networks. Specifically, two pairs of links in those networks are assumed to have the same volume-delay functions. The occurrence of Braess' paradox for this specific case of network symmetry was investigated by Pas and Principio in 1997. Such a symmetry is not common in real-life networks because the parameters of volume-delay functions are associated with roads physical and functional characteristics, which typically differ from one link to another (e.g. roads in networks are of different length). Our research provides an extension of previous studies on Braess' paradox by considering arbitrary volume-delay functions, i.e. symmetry properties are not assumed for any of the network's links and the occurrence of Braess' paradox is studied for a general configuration.

The present article reviews the effects of wartime and post-war policies on regional agglomeration of landuse and transportation activities in Japan. For this purpose the authors have formulated a long-term model over the period 1920–85, and conducted its final test. After confirming the accuracy of the entire model, it is used to evaluate the wartime policies which caused excessive employment agglomeration in Tokyo, and post-war policies concerning the high speed Shinkansen rail network. We conclude that the choices of alternative policies would have led to a more balanced regional structure than there is now, with less agglomeration in both Tokyo and the Kanto region.

A new study by the U.S. Advisory Commission on Intergovernmental Relations focuses on the adaptions in transit services, finances, institutions, and policy processes occasioned by current financial stress at all levels of government and by the devolution of national responsibilities to the state and local governments. This study found, in part, that (1) most metropolitan transportation planning organizations now are locally governed and staffed. (2) their planning is becoming increasingly isolated, less comprehensive, and shorter range. (3) some such organizations are experiencing strong pressure to decentralize or subregionalize, and (4) the desire for these organizations to exercise more effective areawide leadership is not matched with local approval of greater powers for them. The study concludes that informal coordination techniques or new powers granted by state legislatures are the two most likely facilitators of improved metropolitan transportation leadership in the 1980s.

In this study we analyze the dmographic and geographical distribution of pedestrian accidents (n=28,452) in the Quebec Municipalités régionales de comté (MRC) reported between January 1, 1983 and December 31, 1988. In order to be able to make comparisons between MRCs, we have created in Comparative Mortality Index and a Comparative Morbidity Index. We use a logistic regression model to single out explanatory factors. The main tendencies which are apparent in the demographic analysis are an overrepresentation of young persons and elderly persons in the accident statistics, and that men are more at risk than women. Men 15 years and under and men 65 years and over are more at risk of being involved in a fatal pedestrian accident. The geographic analysis show that among men, the average mortality rate is one and a half times greater in rural MRCs than in urban MRCs; among women, rural mortality is two and a half times greater than urban mortality. In the case of non-severe injuries we note an over-representation of urban MRCs. Young persons 15 years or less who live in an urban, populated zone are those most at risk of being involved in a pedestrian accident. Identifying high risk groups or areas is a prerequisite step for injury prevention and control.

TAXI 2000 is the result of a comprehensive process of “top-down” design optimization beginning “from scratch” and subject to a variety of practical constraints. It builds on over two decades of work on automated transit in virtually every industrialized country and on a comprehensive theory of transit economics and technology developed by the author. The system's low cost is a result of discovery of optimum configurations and of technology advances not available a decade ago. The paper includes a description of the system and the process of and basis for its development; discussions of technical areas of dependability, safety, evacuation and rescue, power requirements, and performance; discussions of the state of development, development plans, process of certification, and problems in implementation of the PRT concept.

Transit vehicles stopping to load/unload passengers on-line at a signalized intersection can obstruct the flow of other vehicles. The TRANSYT model ignores the delay to other traffic caused by this loading/unloading process. This can cause TRANSYT to use incorrect flow profiles, resulting in signal timings that cater to these profiles rather than the actual ones. This paper describes a new model for representing near-side transit stops in lanes shared by public transit and private vehicles, and its implementation into the TRANSYT-7F program. The results of an initial application of the proposed model are also described. The proposed model, which is a deterministic simulation model, is able to represent the effect of near-side transit stops on the other traffic; this representation covers both total and partial blockage of the approaches during the transit loading. The procedure has been incorporated into the TRANSYT-7F program. This allows appropriate representation of the adverse effects of transit loading on-line during a green phase. It thus encourages the TRANSYT optimizer to push transit loading to the red phases.

Expo 86, the World Exposition held last year in Vancouver, Canada, was the largest, special-category world's fair ever staged, with 54 international participants. Given the designated theme of transportation and communications, it is interesting to interpret the statements made by the participants in regard to particular sub-theme areas such as urban transit. This paper reviews the presentations (exhibits, demonstrations, conferences, and seminars) developed by all participants in Expo 86 in regard to urban transit technology, and assesses the significance and direction of technological developments in the areas of vehicle and terminal design, network and system operation and control, and planning and management systems.

The average annual daily traffic (AADT) volumes can be estimated by using a short period count of less than twenty-four hour duration. In this paper, the neural network method is adopted for the estimation of AADT from short period counts and for the determination of the most appropriate length of counts. A case study is carried out by analysing data at thirteen locations on trunk roads and primary roads in urban area of Hong Kong. The estimation accuracy is also compared with the one obtained by regression analysis approach. The results show that the neural network approach consistently performed better than the regression analysis approach.

A cost optimized design method of steel bridge girders is studied by using the specifications of the American Association of State Highway and Transportation (AASHTO) Working Stress Design (WSD) method and Load Factor Design (LFD) alternates. Here, cost trade-offs for the steel plate (e.g., the base price plus extras for size, grade, testing and inspection, etc.), stiffeners and splicing are weighed throughout the entire span to minimize the objective function. The method is then applied to a set of over 30 steel bridge structures which collected from various state bridge inventories in order to obtain optimal cost configurations for both WSD and LFD methods. These results are analyzed by a linear regression model to define relationships between cost differences and bridge lengths. From these comparisons, conclusions are drawn to provide the guidelines. It is believed that effective application of these guidelines should lead to more economical designs, especially under the LFD method.

Bus drivers' aberrant behaviors such as errors and violations might bring about extra fuel consumption and mechanic abrading. To investigate how the aberrant behaviors affect the fuel and maintenance costs, seven indexes are proposed and their corresponding threshold values are determined through the field experiments. Nearly six months of en route data are collected from an intercity bus route and the raw data are converted into the proposed index values by a database management system. A collinearity test is performed and three different specifications of simultaneous-equation regression models are attempted. The results show that abnormal engine rotation, unstable speed gradient, remarkable jerk, and speeding are the four independent indexes which can significantly explain the effects of bus drivers' aberrant behaviors on fuel and maintenance costs. Based on the cost importance of these four indexes, the drivers are further clustered into five categories and some practical applications are addressed.

This study developed an approach for measuring elderly passengers' abilities and to explore their difficulties in accomplishing the actions and motions required to patronize the bus service. A conceptual framework about the required actions and motions in bus-taking was established and a questionnaire with 18 items was designed to test their ability to use buses. A face-to-face survey was conducted to collect self-rated information from 304 elderly bus passengers in Taipei. The Rasch model was applied to estimate the difficulty of each item and the ability of each person to use a bus. Results showed the relatively difficult items primarily involved keeping balance on the moving bus, reading the posted information at the station, and recognizing the buses approaching the stations; the levels of physical ability were negatively associated with the respondent's age. Suggestions are made based on improving the facilities or services to help the elderly passengers achieve the necessary actions or motions for using the bus service. Copyright © 2010 John Wiley & Sons, Ltd.

This paper introduces a method that simultaneously analyzes travel variables from stated preferences that are measured under each of several different assumptions. The method uses least absolute deviation estimators and linear programming solutions and is flexible enough to permit inclusion of constraints for ordinal data and latent variables. Travel behavior is characterized by different indicators such as travel time, waiting time, mode choice and departure time. Consideration of different response variables simultaneously as part of a stated preference model requires a reclassification of variables as either endogenous or exogenous. This concept was introduced by the author as structural conjoint analysis earlier. Each endogenous variable may be defined as nominal, ordinal or cardinal and may be either explicitly measured or latent. Current econometric and psychometric techniques cannot accommodate this variety of data. The procedure is essentially a two-stage least absolute deviation simultaneous equation regression. The estimation technique is well known as are the various hypothesis tests. In the method each relationship between endogenous and exogenous variables is formulated separately carefully incorporating assumptions about each type of data. Thus there are different formulations for endogenous variables that are nominal and latent, ordinal and explicit, ordinal and latent, cardinal and explicit and cardinal and latent. Formulations for nominal latent, ordinal explicit and cardinal explicit variables were tested with simulated data for three separate hypothetical problems. Each problem consisted of at least two different types of variables and the technique was found to be able to reproduce the simulation function coefficients in virtually all cases.

This paper develops a mathematical model that is based on the absorbing Markov chain approach to describe taxi movements, taking into account the stochastic searching processes of taxis in a network. The local searching behavior of taxis is specified by a logit form, and the O-D demand of passengers is estimated as a logit model with a choice of taxi meeting point. The relationship between customer and taxi waiting times is modeled by a double-ended queuing system. The problem is solved with a set of non-linear equations, and some interesting results are presented. The research provides a novel and potentially useful formulation for describing the urban taxi services in a network.

Capacity measurement of roads under mixed traffic conditions as prevailing in India is ambiguous as it varies with time, composition of traffic and roadway encroachments. High incidence of slow moving vehicles and tricycles adds to the problem. Volume - capacity ratio appears to be an inadequate measure of defining level of service under mixed traffic situations. An attempt is made in this paper to explore the possibility of presenting unconventional parameters like standard deviation of speed, co-efficient of variation of speed and acceleration noise as possible measures of level of service. Tentative ranges of acceleration noise are proposed in association with flow and speed to explain level of service of urban roads catering to mixed traffic. The results are based on a study conducted in Madras, a major metropolitan city of India.

This research attempted to analyze the impacts of the enhancement of access modes to the main water transportation mode in Bangkok, Thailand. In order to achieve this purpose, access mode choice behaviors are modeled using the probability distribution function (PDF) model, the multinomial logit (MNL) model, and the nested logit (NL) model. The study also attempted to analyze the catchment areas for different access modes and the factors affecting them. Factors affecting the extent of the catchment area such as main haul distance were evaluated. Based on survey results, service attributes such as access cost, in-vehicle travel time, and out-of-vehicle travel time (OVTT) were found to have a significant impact on access mode choice behavior. Socioeconomic factors such as age, gender, income, and occupation were found to affect access mode choice behavior as well. Apart from these factors, trip departure time, egress mode used, and main haul distance were also found to affect access mode choice behavior. It was evaluated that the NL model is most suitable to model access mode choice behavior. A selected NL model was applied in order to predict the impacts of adopting different policies. It was found that reducing in-vehicle travel time, waiting time and/or cost of the bus ride gave most significant impact on the enhancement of access modes. As results of this study, various methods have been suggested to enhance the access/egress service of the water transportation. Copyright © 2010 John Wiley & Sons, Ltd.

The ground access system at Singapore Changi Airport is analyzed. The emphasis is on understanding traffic characteristics and utilization of access facilities. The applicability of typical ground access planning parameters recommended for western airports to Changi Airport is also investigated. Peak traffic levels are found to be manageable. The curbside is the critical link of the access system but congestion in peak periods do not last very long at present. Although the two public car parks together provide enough parking spaces, the closer-in car park is always full in the evening, while the cheaper car park is usually half empty even though it is only 250 m farther. This suggests convenience is more important than cost to most users.

In this paper, we investigate theoretical constructions and properties of three interrelated travel demand management measures including marginal cost pricing, access control, and pollution charge under dynamic traffic assignment framework. For congested traffic networks modeled by the two vertical queue models, that is, the whole link model and the deterministic queuing model, on which flows are controlled, we derive dynamic marginal costs for paths and users' external costs for controlled links. As a strategy to implement the access control, the access pricing is formulated as a dynamic system optimal assignment with access (e.g., traffic volume, queue) control problem, wherein the access constraints represent the restrictions on the traffic volumes and/or environmental constraints. For the whole link model case, an optimal control problem formulation is adopted to investigate the dynamic traffic equilibrium. We derive and discuss the necessary condition for operating the transportation system with capacity/environmental constraints optimally. For the deterministic queuing model case, the inflow to a bottleneck is saturated such that no queue would be formed. The dynamic externalities of the two models are compared. It is found that different externality structures of the two models result in different tolling structures to achieve dynamic system optimal assignment. On the basis of this access pricing analysis and an “equivalent” environmental capacity that converts the environmental constraint into traffic volume restriction, we investigate the traffic-induced air pollution pricing scheme. Copyright © 2012 John Wiley & Sons, Ltd.

Four transportation handicapped groups are identified in Taiwan (impaired ambulation, visually impaired, aged, and others) and nine accessible transportation alternatives are proposed. The costs and potential ridership for these nine alternatives in the Taipei area are estimated. Using analytic hierarchy process (AHP) and multicriteria evaluation with qualitative and quantitative data (MEQQD) methods, the most appropriate accessible transportation alternatives for each of the four handicap groups are selected. It is found that the best accessible transportation alternative for the impaired ambulation, the aged, and others would be a demand‐responsive lift‐equipped specialized van, while half‐fare subsidized taxi would be the second‐best option. By contrast, the best alternative for the visually impaired would be half‐fare subsidized taxi, while conventional bus with broadcast equipment would be the second‐best choice.

This paper examines the degree of compliance with the accident reporting requirements imposed by the Bureau of Motor Carrier Safety (BMCS) of the U.S. Department of Transportation on motor carriers involved in interstate and foreign transport. It also examines the reliability and validity of the accident information reported by these carriers to the BMCS. The study shows that there is a high degree of accident underreporting, especially by the private and exempt carriers, and that the information reported on variables such as cargo weight, gross vehicle weights, and usage of seat belts at the time of accident, is biased toward the interests of the reporters of the accidents.

To reduce injuries in road crashes, better understanding is needed between the relationship of injury severity and risk factors. This study seeks to identify the contributing factors affecting crash severity with broad considerations of driver characteristics, roadway features, vehicle types, pedestrian characteristics and crash characteristics using an ordered probit model. It also explores how the interaction of these factors will affect accident severity risk. Three types of accidents were investigated: two-vehicle crashes, single vehicle crashes and pedestrian accidents. The reported crash data in Singapore from 1992 to 2001 were used to illustrate the process of parameter estimation. Several factors such as vehicle type, road type, collision type, location type, pedestrian age, time of day of accident occurrence were found to be significantly associated with injury severity. It was also found that injury severity decreases over time for the three types of accident investigated.

This paper presents a macro empirical study of injuries and severity, and their contributory factors, for heavy truck accidents. This analysis is carried out through the examination of the fatal injury and non-fatal injury odds ratio indices for a statistically best-fit, log-linear model. The statistical procedures used were the stepwise, backward elimination, log-linear modeling with a critical significance level of 0.05. The analysis was conducted on the set of accident severity contributory independent variables (main-effects) and all possible two-way interactions of these variables (interaction effects) for articulated heavy trucks. Among the findings of the study is that it would appear to be more effective to decrease the accident rates for these trucks rather than to try to limit their resulting severities in attempting to reduce the toll of heavy truck accidents.

This paper describes the process of developing a GIS-based traffic accident information system. A roadway network in Kent County, Delaware, was selected to demonstrate the graphic database. The development of the graphic and attribute databases on a workstation environment is described. Software was developed to graphically represent accident information pertaining to any point on the roadway network, and outputs for typical case scenarios are presented. The software also has the capability of displaying historical accident information pertaining to the site. This aspect would be helpful to the planner or designer in studying the impact of a particular roadway design with respect to safety. Some thoughts for future extensions of this study are also presented. Finally, it is concluded that a carefully designed GIS system can efficiently help transportation professionals with traffic safety studies and that its capabilities can be extended to include other areas such as pavement and inventory management, transit applications, and executive information systems.

The Seoul Metropolitan Government has introduced a quasi-public operational system since the public transport systems were reformed in July 2004. Thus, there has been controversy on moral hazards. A question addressed by researchers of transportation is the extent to which the public transport reforms have led to improvements in efficiency and productivity growth. The directional distance function and the Malmquist Luenberger Index, respectively, were used to investigate the impacts of public transport reforms on efficiency and productivity growth both with and without accident costs in Seoul's bus industry. The data cover 2003 and 2005; 2003 is the pre-reform year and 2005 is the post-reform year. It is found that the overall productivity increased a little regardless of the consideration of accident costs; it increased a little bit more in the presence of accident costs. This means that the overall productivity at least did not decrease and the level of service in terms of safety was improved following the public transport reforms. Copyright © 2011 John Wiley & Sons, Ltd.

Realistic predictions of the likely safety performance of advanced transport systems will need to draw on the knowledge accumulated from a large number of safety evaluations which have already been undertaken for existing transport systems. In particular, safety evaluations of future technologies must avoid the methodological pitfalls experienced in extensively researched areas, such as road safety, if such evaluations are to be meaningful. This paper reviews the use of exposure for a broad range of road safety studies, and concludes that unsatisfactory treatment of exposure is a common failing in past evaluations of the effectiveness of road accident countermeasures. Whilst a broad range of safety analyses is discussed, the use of exposure in site safety studies is emphasized. A follow-up paper will extend the discussion to other aspects of accident exposure including exposure measures for large groups of transport system users.

Accident histories and other related records of elderly drivers were used to develop a profile of the accident prone older driver in Michigan. Elderly drivers were defined as drivers with age greater than or equal to 65 years. The variables used in the study were developed by stratifying drivers age, sex, and residency; type of accident and violation; and number of traffic infraction points received. Comparisons were made between these strata, and the statistical significance of observed patterns in cross tabulated data was tested by performing the chi-square test. The results of the study indicate that, by and large, the elderly drivers from urban areas as compared to those from rural areas, and male drivers as compared to females are more likely to be cited for traffic violations. The statistical analysis showed some recognizable traits of the “young” elderly drivers that suggest prioritized safety countermeasures oriented toward them.

Part I of this paper has argued that any meaningful evaluation of transport system safety must include a consideration of the exposure to accidents, and has demonstrated the use and limitations of several measures of exposure at intersections and along links of the network. To complement this treatment of site exposure, this part of the paper will describe the use of group exposure measures in the assessment of risks incurred by people within particular population groupings. The use of induced exposure measures is also briefly reviewed.

The injury of a child pedestrian by a motor vehicle is the result of a complex combination of circumstances involving elements of child behavior, the behavior of the driver of the vehicle and a host of environmental factors. This paper reports on a study of the significance of physical environmental factors on children's' pedestrian accidents, using data drawn from 786 police reports on child pedestrian accidents occurring on the Island of Montreal between October, 1980 and March, 1982. A series of statistical tests are conducted to examine the effect of temporal variables (month, day, time of day), pedestrian characteristics (age, sex), accident location descriptors (intersection, mid-block, etc.) and environmental characteristics (adjacent land-use, road type, etc.). Remedial measures that are expected to be most effective in reducing the incidence of child pedestrian accidents in large urban areas are proposed.

The research reported in this paper examined the relationship between accidents of elderly drivers and intersection traffic control devices. The analysis was performed using the induced exposure method, where the exposure to an accident is defined as the probability of being the driver not cited for the accident occurrence. The results indicate that the accident involvement of elderly drivers is higher than that of the other drivers under certain circumstances. To reduce these rates modifications in the licensing procedures and training programs are suggested.

Pavement maintenance is essential for ensuring good riding quality and avoiding traffic congestion, air pollution, and accidents. Improving road safety is one of the most important objectives for pavement management systems. This study utilized the Tennessee Pavement Management System (PMS) and Accident History Database (AHD) to investigate the relationship between accident frequency and pavement distress variables. Focusing on four urban interstates with asphalt pavements, divided median types, and 55 mph speed limits, 21 Negative Binomial Regression models were developed for predicting various types of traffic accident frequencies based on different pavement condition variables, including rut depth (RD), International Roughness Index (IRI), and Present Serviceability Index (PSI). The modeling results indicated that the RD models did not perform well, except for predicting accidents at night and accidents under rain weather conditions; whereas, IRI and PSI were always significant prediction variables in all types of accident models. Comparing the models goodness-of-fit results, it was found that the PSI models had a better performance in crash frequency prediction than the RD models and IRI models. This study suggests that the PSI accident prediction models should be considered as a comprehensive approach to integrate the highway safety factors into the pavement management system. Copyright © 2010 John Wiley & Sons, Ltd.

Valuation of travel time savings is a critical measure in transport infrastructure appraisal, traffic modelling and network performance. It has been recognised for some time that the travel times associated with repeated trips are subject to variation, and hence there is risk embedded in the treatment of expected travel time. In the context of the expected utility framework, we use a nonlinear probability weighting function to accommodate choice made under risk. Although the empirical findings suggest small differences between the value of expected travel time savings (VETTS) in the presence and absence of risk, the mean estimate does make a noticeable difference to time benefits when applied to real projects. By incorporating nonlinear probability weighting, our model reveals that the probabilities associated with specific travel times that are shown to respondents in the choice experiment are transformed, resulting in overweighting of outcomes with low probabilities and underweighting of outcomes with high probabilities. Copyright © 2010 John Wiley & Sons, Ltd.

A fast emerging component of the urban transportation problem in cities of the Third World is the problem of traffic congestion. Rapid increases in car ownership coupled with poor land use planning, inadequate road space, lack of regulated parking systems, uneducated use of the road by pedestrians, and bad driving behavior of motorists have all combined to produce congestions comparable to those experienced in cities in the advanced parts of the world. Traffic management measures have been tried in some of the major cities such as road expansion and redistribution of land uses in city centers, but most have produced minimal results. It is recommended in this paper that city authorities adopt an integrated approach to congestion with emphasis on influencing the behavior of the road users.

This paper examines the urban transport system in a typical Sub-Saharan city — Accra, Ghana. A description of its demand and supply characteristics is carried out. Deficiencies in the operation of the system are discussed and suggestions of possible actions that should be taken towards the development of coherent urban transport policies are given. The focus of these suggestions is the establishment of a transportation data collection agency to collect and collate relevant data on the transportation system. This is fundamental to any analysis that is to be done. The need to tackle urban transport problems in a more scientific way and for producing trained local transportation professionals is also emphasized.

Recent advances in traffic control methods have led to flexible control strategies for use in an adaptive traffic control system (ATCS). ATCS aims at controlling the imminent traffic, which is yet to arrive and hence not known perfectly. Therefore, volume prediction is an essential part. Associated with the prediction are two aspects: resolution and accuracy. Recent studies indicate a tradeoff between prediction resolution and accuracy: finer resolutions, larger errors. It is imperative to study the relationship and tradeoff between the control strategy, prediction resolution, and its associated error, which are crucial to the development of ATCS. This study investigates this relationship through an extensive simulation of scenarios in Hong Kong with a recently developed dynamic traffic control model, DISCO. Based on the Hong Kong scenarios conducted with DISCO, the major findings include: (i) the importance of resolution outweighs that of error; (ii) dynamic timing plans generally outperform time-invariant timing plans; (iii) up to a certain extent, overestimated predictions lead to better results than underestimated predictions.

Through an examination of the dependence of several key performance parameters of a public bus system upon Automatic Vehicle Location (AVL) estimation accuracy, it becomes possible to place in perspective the value of AVL technology to improved public conveyance performance. Important bus transportation system performance measures dependent upon AVL estimation accuracy are: (1) Headway Control Error; (2) Time-Of-Passage Error, and (3) Required Layover Reserve. An analytical model of the dependence of these bus system performance measures upon AVL estimation error has been constructed. In addition, error models of three basic types of AVL systems, i.e., dead reckoning, proximity, and radio location have been developed and validated by experimental comparisons. By employing both sets of models, i.e. for the bus transport and AVL systems it becomes possible to recommend appropriate AVL technologies that best meet the performance requirements of a public bus service. The accompanying text synopsizes the noted models and provides an example of their use.

User oriented transit service is designed to meet the particular needs of a selected group of travelers. Transit Routes are located to provide convenient linkages between user's origin and destination in such a way that out-of-vehicle time, such as access and transfer time, is minimized. Planning transit routes requires understanding demographics, land use and travel patterns in an area. The dynamic nature of these systems necessitates regular review and analysis to insure that the transit system continues to meet the needs of the area it serves. Geographic Information Systems (GIS) provide a flexible framework for planning and analyzing transit routes and stops. Socioeconomic, demographic, housing, land use, and traffic data may be modeled in a GIS to identify efficient and effective corridors to locate routes. Part of the route location and analysis problem requires estimating population within the service area of a route. A route's service area is defined using walking distance or travel time. The problem of identifying service areas for park and ride or auto/bus users is not considered here, but assumed analogous to walk/bus trips. This paper investigates the accuracy and costs associated with the use of different attribute data bases to perform service area analysis for transit routes using GIS. A case study is performed for Logan, Utah, where a new fixed route service is operated. The case study illustrates the use of census data, postal data, data collected from aerial photographs, and data collected during a field survey using the network area analysis technique for transit service area analysis. This comparison allows us to describe the amount of error introduced by various spatial modeling techniques of data bases representing a variety of aggregation levels.

All through the twentieth century transportation planning and the implementation of transportation facilities in the developing world was heavily weighted toward motorized transportation (MT), despite the fact that non-motorized transportation (NMT) constitutes a significant proportion of all trips. However, in the last two decades many researchers and practitioners all across the world have recognized the importance and advantages of NMT, and their investigations and findings have contributed toward identifying, if not mitigating, some of the more glaring problems in these countries. Unfortunately, most of these investigations have been performed in a piece-meal and disjointed fashion. This paper explores the complex and sometimes poorly understood set of relationships between transportation and its links to a myriad of other factors, such as landuse, sustainability, safety, energy, ethical issues, value of time, telecommunication, environmental justice, and equity. The main objective of this paper is to provide a systemic overview of NMT by describing its multi-dimensional aspects and to assist developing countries in formulating an “Agenda for Action”.

The record of public involvement in the transportation planning process in the United States has been uneven and, at times, disappointing. It is therefore a matter of some satisfaction that the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA), recognizes that public involvement and input is essential in transportation plan-making. However, little guidance is available to planners as to how participatory democracy could possibly be enhanced and improved in the existing transportation planning process. As matters stand today, the predominant use of technical rationality in the planning process, to the exclusion of communicative action, has probably been the biggest problem.This paper introduces the concepts of communicative action to buttress and complement technical rationality, currently used in the transportation planning process. A real-life case-study is presented to demonstrate how communicative action was successfully used in a problem-ridden planning situation. Validity claims as suggested by Habermas in his Theory of Communicative Action are used in this case-study. It is concluded that academic institutions as well as planning agencies will have to make a concerted effort to educate and train planners not only to be involved with the engineering of our infrastructure, but also to be equally concerned with coping with the social, economic and political dimensions of planning.

In this paper the multi-actor multi-criteria analysis (MAMCA) method to evaluate transport projects is presented. This evaluation method specifically focuses on the inclusion of qualitative as well as quantitative criteria with their relative importance, defined by the multiple stakeholders, into one comprehensive evaluation process in order to facilitate the decision making process by the different stakeholders. The MAMCA methodology is introduced by an overview of other evaluation methods for transport projects in the past and is illustrated by means of two practical cases. The introduction will lead us to the theoretical conception of the MAMCA method where we draw the attention to the proven usefulness of the MAMCA for the evaluation of transport projects and the inclusion of different kinds of stakeholders, individuals as well as groups, into the evaluation process.

This paper presents a new cost allocation method developed for estimating the fully-allocated costs of the excess peak hour bus transit service provided by two public transit systems. The estimates were produced for the explicit purpose of carrying out a realistic comparison of these costs and the costs of the potential provision of the same service by private operators. The method utilizes the same service data for the analysis. The pragmatic estimation of the fully allocated costs of service by the public and private sectors enables a more accurate estimation of potential cost savings. Sensitivity analysis was also performed using the same costing procedure to determine the range of cost savings that are feasible in a competitive contract arrangement of private sector providers. The new method separates costs of the direct provision of service from other indirect costs and thus facilitates the identification of each cost item and its significance in comparative cost estimates.

Two three-phase actuated control strategies at diamond interchanges were investigated for different ramp spacings and traffic patterns. An advanced experimental design, hardware-in-the-loop control, was employed for the simulation study. Operational performance was identified in terms of cycle length, average delay and total stops. Experimental results showed that the two phasing strategies gave similar performance in terms of cycle length and average delay, but not stops. The cycle length of three-phase operation increased slightly as the ramp spacing became wider. The delay of each strategy was dependent on the traffic pattern, but there was a distinct movement preference for each strategy. The total stops decreased as the spacing increased, and it was the most sensitive variable for the studied traffic demand level. It was also shown that the concept of the hardware-in-the-loop control provides an effective way to evaluate the signal phasing and control strategies.

Road safety is a policy priority due to the high casualties and costs associated with road accidents. Since speed is a major cause of road accidents, in-vehicle speed limiters or Intelligent Speed Adaptation (ISA), seems a promising solution. ISA implementation, however, is hindered by large uncertainties, for example about the impacts of ISA, the way users might respond to ISA, and the relationship between speed and accidents. Traditional Multi-Criteria Analysis (MCA) has limitations in handling these uncertainties. We present an MCA approach based on exploratory modeling, which uses computational experiments to explore the multiple outcomes of ISA policies (safety, emissions, throughput, and cost) across a range of future demand scenarios, functional relationships for performance criteria, and user responses to ISA. As an illustration, by testing the impacts of different ISA penetration levels on two driver groups, we show that when compliance with ISA is expected to be low, a policy aimed only at novice drivers outperforms other ISA policies on safety improvement.

Real-time signal control operates as a function of the vehicular arrival and discharge process to satisfy a pre-specified operational performance. This process is often predicted based on loop detectors placed upstream of the signal. In our newly developed signal control for diamond interchanges, a microscopic model is proposed to estimate traffic flows at the stop-line. The model considers the traffic dynamics of vehicular detection, arrivals, and departures, by taking into account varying speeds, length of queues, and signal control. As the signal control is optimized over a rolling horizon that is divided into intervals, the vehicular detection for and projection into the corresponding horizon intervals are also modeled. The signal control algorithm is based on dynamic programming and the optimization of signal policy is performed using a certain performance measure involving delays, queue lengths, and queue storage ratios. The arrival–discharge model is embedded in the optimization algorithm and both are programmed into AIMSUN, a microscopic stochastic simulation program. AIMSUN is then used to simulate the traffic flow and implement the optimal signal control by accessing internal data including detected traffic demand and vehicle speeds. Sensitivity analysis is conducted to study the effect of selecting different optimization criteria on the signal control performance. It is concluded that the queue length and queue storage ratio are the most appropriate performance measures in real-time signal control of interchanges. Copyright © 2010 John Wiley & Sons, Ltd.

This Taiwan traffic-adaptive arterial signal control model borrowed its traffic flow framework mainly from a British traffic-adaptive control model with a cyclic traffic progression function, i.e. SCOOT (Split Cycle Office Optimisation Technique). The new arterial control model can take into account delays of both major and minor streets and make real-time signal timing decisions with optimal two-way signal offsets, so as to create the best arterial signal operation performance. It has been developed to be an online real-time software for both simulation testing and field validation. Through simulation, it was found that the performance when operating this newly developed real-time arterial traffic-adaptive model was significantly better than when using the optimal fixed-time arterial timing plan. On the aspect of field testing, three signalized intersections located in East District, Tainan City, Taiwan were selected to be the test sites. Fairly good traffic control performance has been demonstrated in that it can effectively reduce travel delays of the control arterial as a whole. Additional discussions about how to combine travel delay and the total number of vehicle stops into a new control performance index have also been included to make the new traffic-adaptive model more flexible and reasonable to meet the expectations of different driver groups in the arterial system.

This paper reports on a study that developed a next-generation Transit Signal Priority (TSP) strategy, Adaptive TSP, that controls adaptively transit operations of high frequency routes using traffic signals, thus automating the operations control task and relieving transit agencies of this burden. The underlying algorithm is based on Reinforcement Learning (RL), an emerging Artificial Intelligence method. The developed RL agent is responsible for determining the best duration of each signal phase such that transit vehicles can recover to the scheduled headway taking into consideration practical phase length constraints. A case study was carried out by employing the microscopic traffic simulation software Paramics to simulate transit and traffic operations at one signalized intersection along the King Streetcar route in downtown Toronto. The results show that the control policy learned by the agent could effectively reduce the transit headway deviation and causes smaller disruption to cross street traffic compared with the existing unconditional transit signal priority algorithm.

Gridlock is defined when traffic comes to a complete halt inducing huge delays. If a work zone on a two-lane two-way highway is set up, in which one of the traffic lanes is closed for maintenance road works, the remaining lane has to be controlled to serve the two-way traffic alternatively. The study objective is to optimize the traffic signal controls across two closely spaced work zones to prevent a gridlock, which can occur easily if upstream and downstream signals are not well coordinated. When vehicle queues build up in the middle sections between two work zones and further expand to occupy the single available lanes in both directions, the two-way traffic is then blocked and no vehicle can leave from the queues generating a gridlock. To address this problem, spatial queues are important parameters that must be explicitly analyzed. The cell transmission model, which is known to be a robust mathematical tool for the modeling of queue dynamics, is adopted in this study. A signal cell is used to represent each traffic signal control, the exit flow capacity of which is defined in accordance with the signal plan. A set of linear constraints is established to relate all of the model parameters and variables. The objective function is taken as the total number of vehicles in the critical section between the two work zones. The minimization of this objective function can effectively obviate the occurrence of a gridlock. The optimization problem is formulated as a Binary-Mixed-Integer-Linear-Program that can be solved by the standard branch-and-bound technique. Numerical examples are given to demonstrate the effectiveness of the proposed methodology. Copyright © 2010 John Wiley & Sons, Ltd.

U-turns are treated as left-turns in the current procedures for estimating saturation flow rates at signalized intersections. While U-turning vehicles are usually mixed with left-turning vehicles in inside or left-turn lanes and conflict with opposing through traffic as left-turning vehicles, the vehicle operating characteristics are different. The objective of this paper is to investigate the effects of U-turns on the traffic flow in left-turn lanes. Field data of 600 headways of left-turning passenger cars and 160 headways of U-turning passenger cars are recorded. The average headways of U-turning passenger cars are found to be significantly larger than those of left-turning passenger cars. The effects of U-turning vehicles depend upon the percent of U-turning vehicles in the left-turn lane, as well as the order of formation in the traffic stream. Adjustment factors for varying percents of U-turning vehicles in left-turn lanes are established.

Suppose that in an urban transportation network there is a specific advanced traveler information system (ATIS) which acts for reducing the drivers' travel time uncertainty through provision of pre-trip route information. Because of the imperfect information provided, some travelers are not in compliance with the ATIS advice although equipped with the device. We thus divide all travelers into three groups, one group unequipped with ATIS, another group equipped and in compliance with ATIS advice and the third group equipped but without compliance with the advice. Each traveler makes route choice in a logit-based manner and a stochastic user equilibrium with multiple user classes is reached for every day. In this paper, we propose a model to investigate the evolutions of daily path travel time, daily ATIS compliance rate and yearly ATIS adoption, in which the equilibrium for every day's route choice is kept. The stability of the evolution model is initially analyzed. Numerical results obtained from a test network are presented for demonstrating the model's ability in depicting the day-to-day and year-to-year evolutions.

The failure to decide on the goals and develop advanced transit facilities in the USA and other countries despite much discussion in the last 15 years is pointed out and the reasons for it are considered. The main reason for it was that urban development continued to proceed mostly in medium and low-density areas for which advanced transit is not suitable. It is suggested that this circle of inaction must be broken. It is suggested that the problem of advanced transit be thoroughly reconsidered in order to decide on some realistic and necessary goals.