bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal control of headway variation on transit routes
Authors: Abkowitz Mark , Eiger Amir , Engelstein Israel
Published: January 2010

Headway control strategies have been proposed as methods for correcting transit service irregularities and thereby reducing passenger wait times at stops. This paper addresses a particular strategy which can be implemented on high frequency routes (headways under 10–12 minutes), in which buses are held at a control stop to a threshold headway. An algorithm is developed which yields the optimal control stop location and optimal threshold headway with respect to a system wait function. The specification of the wait function is based on the development of several empirical models, including a headway variation model and an average delay time model at control stops.

A conclusion is reached that the headway variation does not increase linearly along a route, a common assumption made in many previous studies. Furthermore, the location of the optimal control stop and threshold value are sensitive to the passenger boarding profile, as expected. The algorithm itself appears to have practical application to conventional transit operations.
Changing relationships in the financing of elderly and handicapped transportation services
Authors: Walther Erskine S.
Published: January 2010

This paper reports the results of a national survey of providers of specialized transportation services who are recipients of UMTA Section 5 or Section 9 funding and report owning demand responsive vehicles (Section 15 report). The study reports a variety of service measures, financial data, cost containment activities and related information for fiscal years 1980 and 1982. For a limited number of systems, financial data for fiscal year 1984 are also reported.

Analysis of the data indicates a general but as yet uncertain trend towards declining UMTA participation in funding these systems, increased fares and increased usage of cost containment and cost reduction techniques by the responding systems. Should the reported trends continue, then the responding systems could be expected to have financial difficulty in complying with the currently proposed regulations for the enforcement of Section 504 of the Rehabilitation Act of 1973.
Aggregation effects on the network design problem
Authors: Haghani Ali E. , Daskin Mark S.
Published: January 2010

This article examines the effects of various network extraction schemes on the network design problem. Given an original network, many criteria can be used to identify subnetworks on which the network design problem is solved. For the purposes of this article, these subnetworks are obtained using an extraction algorithm which preserves the magnitude of the user equilibrium flows on the links of these subnetworks. The results of the implementation of the network design problem on the original and the extracted subnetworks are presented and compared. We conclude that very good solutions to the network design problem can be obtained from the use of highly aggregate networks.
Aesthetic markets and a new automated people mover
Authors: Trent Roger B. , Kvashny Alon , Neumann Edward S. , Walukas Elizabeth , Halkias John
Published: January 2010

Research literature suggests that aesthetic response toward a transportation system may be colored by non‐aesthetic values. Photographic depictions of downtown street scenes with and without automated people mover guideways were shown to various community groups. Measures of external utilities—stakes in the local community and in public transportation—bore no relationship to aesthetic assessments of either guideway scenes or street scenes without a guideway. In contrast, aesthetic background and interests depressed evaluations of both guideway and non‐guideway scenes. Aesthetic background evidently influences aesthetic assessments of elevated guideways in urban streets far more than do non‐aesthetic utilities. This suggests that planners of new transportation systems need to address aesthetic impacts apart from other impacts and that aesthetic criteria will be applied more stringently by some community groups than by others.
The transaction cost approach to modeling the demand for automobiles
Authors: Hocherman Irit , Prashker Joseph N. , Ben‐Akiva Moshe
Published: January 2010

The purchase of an automobile involves significant transaction costs in addition to the purchase price. Therefore, the assumptions implied by static car holding models are invalid. This paper describes a dynamic approach to the modeling of level‐of‐ownership and auto‐type choice, based on a transaction choice model which utilizes information on past car ownership. The cost or disutility of a transaction depends on the attributes of the household and the purchased car, as well as on past car‐ownership characteristics. A set of assumptions underlying the incorporation of transaction costs in the model is presented. The paper discusses the econometric implications of omitting the dynamic attributes (i.e., past ownership characteristics). A disaggregate model was estimated, using a choice‐based sample consisting of a random sample of households enriched with a sample of households which transacted in the car market during the study period.

This sampling method combined with a random choice of a subset of the car alternatives provides for a cost‐effective method to estimate a transaction model.
Efficiency of the public and private bus transport sectors in Sri Lanka
Authors: Perera Manisha H.
Published: January 2010

The public and private bus sectors are in direct competition in most bus routes in Sri Lanka. Consequently, Sri Lanka is an ideal location to study their relative efficiencies. Five dimensions of transit performance are analyzed for comparing the relative efficiencies of the two sectors: cost efficiency, labour efficiency, input efficiency, revenue generation and safety. Productivity ratios are utilized for measuring the dimensions of transit performance. The productivity ratios for cost efficiency, labour efficiency in terms of total staff, input efficiency, revenue generation and safety in terms of accidents per bus showed the private bus transport sector to be more efficient than the public bus transport sector.
Bridge sampling for evaluating structural impact of trucks
Authors: Ayyub Bilal M. , Schelling David R. , Fu Chung C. , Hassan Maguid H.
Published: January 2010

In this paper, a method for designing a statistically valid sample of bridges is proposed. The need for such a sampling procedure arises from the impracticality of a detailed analysis of the structural effects of new candidate truck configurations on the whole bridge inventory. In this study, a set of bridges from the national inventory was determined for the purpose of selecting a bridge sample. This set of bridges is referred to as the population. The selection of bridges for inclusion in the population was based on the status of the bridge, type of service, structural material, structural system type and functional class. The stratified sampling method was used in the determination of the required sample sizes. According to this method, the population was first divided into sub‐populations, or strata. These sub‐populations were non‐overlapping. In turn, each strata was divided into sub‐strata. The characteristics of each sub‐stratum were estimated and combined to determine the characterics of the strata. Then the characteristics of the strata were combined to determine the characteristics of the bridge population. A comparison of the results based on the sample and bridge population was conducted in order to verify the validity of the proposed sampling procedure.
An aggregate demand model for domestic airlines
Authors: Ghobrial Atef
Published: January 2010

An econometric model is estimated for the aggregate demand of an airline. The demand is expressed in terms of airline network structure, operating characteristics and firm‐specific variables. A number of model formulations with different combinations of explanatory variables are estimated using the two‐stage least‐square procedure. The results suggest that the airline aggregate demand is elastic with respect to yield, and inelastic with respect to both network size and hub dominance. Some implications regarding airline network expansion and hubbing are discussed.
Air traffic management: Optimization models and algorithms
Authors: Bianco Lucio , Bielli Maurizio
Published: January 2010

Current air traffic control systems are mainly conceived to ensure the safety of flights by means of tactical interventions, because of the difficulty of accurately foreseeing the traffic evolution. In fact, in real traffic conditions, planes are often penalized since sometimes safety standards are redundant.

Today, this management philosophy is no longer valid because of congestion phenomena which often occur in the most important terminal areas. Therefore, as to future control systems it is necessary to introduce not only more automated procedures to keep adequate safety levels, but also planning functions in order to increase the system capacity and to improve system efficiency.

In recent years several studies have been carried out, new control concepts have been introduced and some optimization models and algorithms developed to improve air traffic management.

In this paper a survey of our early works in this field is reported and a multilevel model of air traffic management is proposed and discussed. The functions corresponding to the on‐line control, that is flow control, strategic control of flights and aircraft sequencing in a terminal area, are examined and the optimization models and solution algorithms are illustrated. Finally, relevant problems coped by recent research are mentioned and new trends are indicated.
ICE‐design and operational aspects
Authors: Henn Wolfgang
Published: January 2010

On 2nd June 1991 the high speed rail era in Germany began with the introduction of the ICE (Inter‐city express) on the Hamburg‐Hannover‐Kassel‐Frankfurt‐Munich line, the second ICE line followed one year later. The ICE concept and the technology of the ICE‐train set marks the threshold of the 21st Century and demonstrates the as yet untapped development potential of the wheel‐on‐rail‐system. With the development of the ICE a trainset is available which can be adapted to all European High Speed Rail lines.
Fuzzy evaluation of potential suburban railway station locations
Authors: Smith P. N.
Published: January 2010

A multicriterion evaluation methodology is presented and its applicability demonstrated in the context of identifying the most suitable railway station locations within a set of potential station locations on one of three possible railway line extensions to Brisbane's suburban network. These possible extensions involve the reopening of the Bethania ‐ Beaudesert line for passenger services; the adaptation of the standard gauge Sydney line for extension of passenger services to Greenbank and beyond; and, the development of a spur‐line to Inala and immediate surrounds. The Sydney line is the focus of this paper. The methodology is particularly relevant in the context of options characterized by “soft” data where only linguistic descriptions of the performance of options with respect to criteria are possible. Linguistic variables such as “performance” assuming linguistic values such as “high”, “medium” and “low” are characterized in terms of fuzzy variables, in particular, triangular fuzzy numbers in this study.
Application of time series techniques for forecasting truck traffic attracted by the Bombay metropolitan region
Authors: Dhingra S. L. , Mujumdar P. P. , Gajjar Rajesh H.
Published: January 2010

Knowledge of future traffic flow is an essential input in the planning, implementation and development of a transportation system. It also helps in its operation, management and control. Time series analysis techniques have been extensively adopted for this purpose in the fields of economics, social sciences and in other fields of technology. An attempt has been made in this study to apply the techniques of time series analysis to goods traffic, particularly truck traffic.

Four predominant corridors, N.H.3, N.H.4, N.H.8 and Lal Bahadur Shastri Road (L.B. S. Rd.), accounting for majority of truck movement in the Bombay Metropolitan Region (BMR), have been considered for modeling. Raw data was processed initially, to obtain an insight into the structure of time series. Ten candidate models of the Auto‐Regressive Moving Average (ARMA) and Auto‐Regressive Integrated Moving Average (ARIMA) family are investigated to represent each of the four corridors. Models finally proposed, to represent each of the four corridors have been selected based on Minimum Mean Square Error (MMSE) and Maximum Likelihood Rule (MLR) criteria. Models ARIMA (2, 1, 0), ARMA (1.0), ARMA (1, 1) and ARIMA (1, 1, 0) are proposed for N.H.3, N.H.4, N.H.8 and L.B.S. Rd. respectively, based on significant weekly periodicity.
Comparison of results of two models of transportation demand in Hong Kong: CDAM and a version of microTRIPS
Authors: Lam William H. K. , Hai‐Jun Huang
Published: January 2010

CDAM is a new computer program for solving the combined trip distribution and assignment model for multiple user classes, which enables transport planners to estimate consistent Origin‐Destination (O‐D) matrices and equilibrium traffic flows simultaneously if the trip production and attraction of each user class at zone centroids are available. This paper reports an application of CDAM to the central Kowloon study area in Hong Kong. The coefficients of the model related to the components of generalized costs are calibrated on 1986 travel data. A comparison of results of CDAM and a version of MicroTRIPS models of transportation demand in Hong Kong are presented. Finally, some conclusions are drawn and the advantage of the CDAM are discussed.
Planning for pedestrian networks in North American downtowns
Authors: Zacharias John
Published: January 2010

While North American urban regions are served by mechanical modes of transportation, downtowns are largely pedestrian environments. The growth and consolidation of office districts over the last twenty years have revived interest in developing coherent and efficient pedestrian networks, which can be coordinated with other transportation needs within the downtown. Ambitious plans for expansion of the downtown for offices, the retail and service industries as well as for housing and entertainment have been adopted in many North American cities during the 1980s. The successful integration of these large central areas depends to a considerable extent on the implementation of expanded pedestrian networks. This paper discusses certain spatial characteristics of North American cities which call for specific network designs and research into the walking environments of central areas. More knowledge is needed of the relative contributions to pedestrian regeneration of land use combinations, the design of networks and of walking paths.
Facing the realities of non‐motorized transportation in developing countries
Authors: Khisty C. Jotin
Published: January 2010

The objective of this paper is to assess issues concerning non‐motorized transportation in developing countries. This assessment is done through an examination of three topics: a brief overview of the transportation picture in developing countries; a study of city size and city form vis‐a‐vis pedestrian movement; and, a look at the characteristics of non‐motorized modes, including their capacities. An analysis and discussion attempt to sort out the crucial issues connected with pedestrian planning in particular, and non‐motorized transport in general. It is concluded (1) that special attention be paid to space/time capacity/cost issues connected with non‐motorized modes (2)that some of the low‐cost intermediate technology modes be examined for possible inclusion in traffic streams (3)that land‐use patterns need to be rearranged keeping in mind the limitations of non‐motorized modes, and (4)that the extent to which physical trip‐making can be substituted by telecommunication needs to be examined very critically. An agenda for action reflects these concerns.
The role of the physical environment in child pedestrian accidents
Authors: David Naomi Kupferberg‐Ben
Published: January 2010

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.
Cost‐based approach for sizing of pedestrian facilities
Authors: Seneviratne Prianka N. , Javid Massoud
Published: January 2010

Pedestrian facility size is currently determined in direct relationship to the design level of service. However, the design level of service is chosen arbitrarily from the six levels of service, which are assumed to represent the freedom available for movement at different levels of pedestrian flow. This direct and simple approach to facility sizing is shown to have two fundamental deficiencies that contribute to wasteful over capacity. In this article, a cost‐based approach is introduced to overcome the deficiencies. Two analytical models, one for determining optimal design density and another for determining optimal design flow, are presented. The optimum design parameters minimize the total cost of the facility defined as the sum of construction cost and user cost. The sensitivity of the optimum parameters to the cost and pedestrian flow parameters is demonstrated using a numerical example.
Impact of information technology on public transport fares data
Authors: Clark J. M. , Richards M. J.
Published: January 2010

The work described was undertaken as part of the CASSIOPE project in the EC DRIVE programme. A range of fare collection procedures in public transport is described, and the importance of these for data collection by operators is stressed. It is suggested that such data management could be standardized and to this end four case studies were carried out in different European cities. Data models were built for each city, and these models are merged into a preliminary version of a generalized model. The need and uses for such a fare collection data model is explained.
Interactions between driver information, route choice, and optimal signal timing on a simple network
Authors: Nihan Nancy , Hamed Mohammad , Davis Gary
Published: January 2010

The interaction between driver information, route choice, and optimal traffic signal settings was investigated using a simple two‐route system with a single “T” intersection and a fixed O‐D demand. The logit model and the method of successive averages (MSA) were used to calculate the route choice probabilities and the stochastic equilibrium assignment. Given an assignment, signal settings which minimized average intersection delay were calculated; flow reassignment and new optimal signal settings were then obtained and this iterative process continued until convergence. The calculations were performed either directly in a combined assignment/signal optimization model or in stages using the output flows of an assignment model as inputs to TRANSYT‐7F and iterating between the two models. Results show that a unique joint signal timing/assignment equilibrium is reached in all cases provided that a certain precision in drivers' perceptions is not reached. If driver information increases to this precision (bifurcation point) and beyond, results show clearly that the unique joint signal timing/assignment equilibrium no longer exists. In fact, three joint equilibria points exist after the bifurcation point. Two of these points are stable and one is not.

It was found that the system yields the lowest total intersection delay when the joint equilibrium is such that all traffic and hence the major part of green time is assigned to only one of the two routes. Although this may not be feasible to implement in practice, the results indicate clearly for this simple example that there is a trade‐off between a system with minimum total delay but no unique joint signal‐settings/assignment equilibrium (achieved when drivers have nearly perfect information about the system) and a system with a unique joint equilibrium but with higher total delay (achieved when drivers have reasonably good but somewhat limited information). In most cases the second system seems appropriate for a number of practical reasons.
Effect of traffic information on commuters' propensity to change route and departure time
Authors: Khattak Asad J. , Schofer Joseph L. , Koppelman Frank S.
Published: January 2010

Considerable public and private resources are devoted to the collection and dissemination of real‐time traffic information in the Chicago area. Such information is intended to help individuals make more informed travel decisions, yet its effect on behavior remains largely unexplored. This study evaluates the effect of traffic information on travelers' route and departure time changes and provides a stronger basis for developing advanced information systems.

Downtown Chicago automobile commuters were surveyed during the AM peak period. The results indicate that a majority of the respondents access, use and respond to information. For example, individuals use travel information to reduce their anxiety—even if they do not change travel decisions; this indicates that information may have “intrinsic” value. That is, simply knowing traffic conditions is valued by travelers. More than 60% of the respondents had used traffic information to modify their travel decisions. Multivariate analysis using the ordered probit model showed that individuals were more likely to use traffic reports for their route changes if they perceived traffic reports to be accurate and timely, and frequently listened to traffic reports. Respondents were more likely to change their departure times if they perceived traffic reports to be accurate and relevant, and frequently listened to traffic reports.

The implication for Advanced Traveler Information Systems are that they may be designed to support both enroute and pre‐trip decisions. ATIS performance, measured in terms of accuracy, relevance and timeliness would be critical in the success of such systems. Further, near‐term prediction of traffic conditions on congested and unreliable routes (where conditions change rapidly) and incident durations is desirable.
GIS‐based highway design review system to improve constructability of design
Authors: Lee Hosin , Clover Pamela
Published: January 2010

This paper presents a Geographic Information Systems (GIS) as a tool which can help highway engineers review a completed highway design to improve its constructability. The GIS can link different data sets together using geographical location as the common key between the data sets to perform various spatial operations. In this paper, the GIS is used to integrate various highway design data using a common milepost referencing system. The GIS allows the integration of the highway design information by establishing common spatial relationships between various highway design features and their geographical locations. The GIS can provide a comprehensive platform upon which all aspects of the highway project review process can be built. This paper also addresses the interface of GIS with the existing highway project data bases and computer‐aided design files. The proposed GIS‐based highway design review system can improve the constructability of the highway design at an early design review stage.
An analysis of interfacing between signal subnetworks
Authors: Tsao Shou‐min , Rau Li‐kuo
Published: January 2010

The objective of this study is to analyze the behavior of offsets between traffic signal subnetworks. If different cycle lengths are used for adjacent subnetworks, the relative timing between the subnetworks will deviate from the original setup. A generalized mathematical model is developed, which demonstrates the cyclic timing patterns of offsets between subnetworks with different cycle lengths. The offset cycle time is equal to the Least Common Multiple (LCM) of the cycle lengths of the adjacent subnetworks. A TRAF‐NETSIM model is used to examine how the cyclic behavior of offsets should be considering in timing the subnetworks, and in reconciling different offset requirements between more than two subnetworks.
Energy savings due to land transportation management in Singapore
Authors: Fwa T. F. , Ang B. W.
Published: January 2010

Singapore has been actively engaged in implementing various land transportation policies and traffic management schemes since the early 1970s to reduce traffic congestion. This paper examines the benefits in energy savings arising from the following five major schemes: (a) the Area Licensing Scheme, (b) the computerised Area Traffic control System, (c) the adaptive traffic control system, (d) the exclusive bus lane scheme, and (e) the island‐wide expressway system. The analyses are made based on the findings of a two‐year study that developed vehicle fuel consumption models for Singapore traffic. The Area Licensing Scheme that restricts traffic flow into the Central Business District (CBD) is found to have the greatest energy impact, followed by the island‐wide expressway system and the traffic‐signals control systems within the CBD.
A stated preference examination of time of travel choice for a recreational trip
Authors: Hunt J. D. , Patterson D. M.
Published: January 2010

A stated preference experiment was performed in Calgary in Canada to examine how people are influenced in the selection of a departure time for a hypothetical trip to see a movie. A total of 635 complete observations were obtained. In each observation the respondent was presented with a set of possible departure time scenarios and asked to indicate the order of preference for these scenarios. Each scenario was described by specifying the automobile travel time, the expected arrival time relative to the movie start time, the parking cost, the probability of being at least ten minutes late for the movie and the length of time the movie had been running. This forced the respondent to trade off between conditions regarding these attributes. Age, gender and frequency of movie attendance were also recorded. The observations thus obtained were used to estimate the parameter values for a range of alternative utility functions in logit models representing this choice behaviour. The results indicate that all of the attributes included have significant effects on departure time choice in the situation being considered. They also indicate that travellers are prepared to arrive roughly two minutes early for each minute of travel time saved; that the money value of driving time for trips to recreational activities is about half that for trips to work; that one additional percent in the probability of arriving late is equivalent to roughly 0.20 Canadian dollars or 1.93 minutes drive time; and that there is a preference for a non‐zero expected early arrival time regardless of the associated probability of arriving late. Some of these results are novel and others are consistent with findings for work trips in work done by others, which is seen to add credence to the approach being used here.
Evaluation of congestion trends on chicago expressways
Authors: Polus Abishai
Published: January 2010

The growth in congestion on Chicago area expressways has had a major effect on almost all aspects of the region's economy, travel behavior and land‐use development patterns. The objective of this study was to evaluate congestion trends on Chicago's expressways during the last decade (1980 to 1989) by quantifying the magnitude and tendencies of congestion for the various expressways.

This study concentrated on an analysis of the minute‐miles of congestion (MMC), a measure that provides an averaged section congestion during a given time period and that is continuously collected by the Illinois Department of Transportation for all Chicago‐area expressways. The MMC offers a relatively accurate and unbiased estimate of the quantity and duration of congestion.

In order to compare congestion trends on the area's ten major expressways in the 1980's it was decided to evaluate the yearly Cumulative Distribution Function of congestion. This analysis was conducted for both the inbound and outbound directions and for the A.M. and P.M. daily peak periods.

The magnitude of congestion was found to increase considerably with the years from 1980 to 1989. The increase in congestion for “reverse commuting”, trips to the suburbs in the morning peak and from the suburbs in the evening peak, grew more substantially than the increase in the regular “city commute.” The reason for this phenomenon was the rise in job opportunities in the suburbs, resulting partially from increased congestion and reduced accessibility.

Additional analysis showed that the duration of the peak period, defined by the time in which congestion exceeded a predetermined threshold level, was generally longer for the “city commuting” than for the “reverse commuting.” Comparison of congestion among seasons, showed that the most congested season was usually the spring (May 1 to June 15). The system analysis showed that the by 2000, the expected system congestion will be more than twice the 1980 system congestion.
Transit assignment under crowded conditions
Authors: Tian Zhili , Yang Hai , Lam William H. K.
Published: January 2010

This paper presents a transit assignment algorithm for crowded networks. Both congestion in vehicles and queuing at stations are explicitly taken into account in predicting passenger flows for a fixed pattern of origin‐destination trip demands. The overflow effects due to insufficient capacity of transit lines are considered to be concentrated at transit stations, while the in‐vehicle congestion effects (or discomforts) are considered to be dependent on in‐vehicle passenger volume. Overflow delay at a transit station is dependent on the number of excess passengers required to wait for the next transit car. We use a logit model to determine the split between passengers that chose to wait for the next transit car and passengers that chose to board on the alternative transit lines. The proposed algorithm predicts how passenger will choose their optimal routes under both queuing and crowded conditions.
Citizen participation through communicative action: Towards a new framework and synthesis
Authors: Khisty C. Jotin , Leleur Steen
Published: January 2010

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.
Intercity rail services: A nested logit stated choice analysis of pricing options
Authors: Hensher David A.
Published: January 2010

There is a renewed interest in intercity and long‐distance rail services in many countries, with both new high‐speed rail services and improvements to conventional rail under review. The current study reports on an investigation using a stated choice experiment, of the demand for sleeper services between Sydney, Northern New South Wales (NSW) and Brisbane in Australia, a 12 to 14 hour trip, just after a decision by the NSW government to temporarily suspend sleeper services and introduce seating service only, pending an inquiry into the demand for such loss‐making services under alternative price and service levels. A matrix of direct fare elasticities within the rail mode and between rail and competing modes are obtained for concession and non‐concession travellers from a nested logit model. The empirical evidence extends our knowledge of the sensitivity of the long distance passenger market to a range of rails fares, distinguishing between classes of fares and levels of service.
Joint optimization of a rail transit line and its feeder bus system
Authors: Chien Steven , Schonfeld Paul
Published: January 2010

A model is developed for jointly optimizing the characteristics of a rail transit route and its associated feeder bus routes in an urban corridor. The corridor demand characteristics are specified with irregular discrete distributions which can realistically represent geographic variations. The total cost (supplier plus user cost) of the integrated bus and rail network is minimized with an efficient iterative method that successively substitutes variable values obtained through classical analytic optimization. The optimized variables include rail line length, rail station spacings, bus headways, bus stop spacings, and bus route spacing. Computer programs are designed for optimization and sensitivity analysis. The sensitivity of the transit service characteristics to various travel time and cost parameters is discussed. Numerical examples are presented for integrated transit systems in which the rail and bus schedules may be coordinated.
Transit fare differentials: A theoretical analysis
Authors: Ling Jui‐Hsien
Published: January 2010

This paper compares the ridership. operator revenue, passenger‐km, and consumer surplus in uniform pricing policy versus the differential fare pricing system. The comparisons are assumed that the flat fare is set equal to average differential fares. With mathematical derivation, the paper investigates some of the properties of fare differentiation and discusses characteristics of a general nature. The theoretical results have spelled out the conditions under which pricing policy may yield higher performances. A simple numerical example is used to demonstrate the sensitivity of the model. Some recommendations for setting transit pricing policy are drawn from the results.
An iterative group‐based signal optimization scheme for traffic equilibrium networks
Authors: Wong S. C. , Yang Chao
Published: January 2010

This paper presents an iterative scheme for a combined signal optimization and assignment problem, using a traffic model from the well‐known procedure TRANSYT. The signal settings are optimized by means of a group‐based technique, in which the signal timings are specified by the common cycle time, the start time and duration of the period of right of way for each signal group in the network. The optimization problem was formulated as an integer program and solved by a set of heuristics. Given the optimized signal settings determined from the group‐based technique, a path‐based assignment algorithm is employed to obtain the equilibrium traffic pattern using the sensitivity information for TRANSYT model and a Frank‐Wolf method. Based on the equilibrium flow pattern, the group‐based optimization algorithm is then used to determine a better set of signal timings. The procedure is repeated until certain convergence criteria are satisfied. A numerical example is employed to demonstrate the benefits obtained from this iterative scheme. Encouraging results are obtained.
Sizing parking facilities at airports
Authors: Javid Massoud , Seneviratne Prianka N. , Kakimoto Ryuji
Published: January 2010

Established rules‐of‐thumb and industry guidelines for estimating the supply of parking at airports are based on uncertain quantities such as design year enplanements and number of airport employees, and are independent of cost. In the presence of continued uncertainty and increasing competition for limited space in and around airports, it is important that facilities are sized in relation to cost of providing and using them. A probabilistic model based on the classical “newsboy” problem is proposed to determine the optimal supply of parking in relation to expected total cost while treating demand as a random quantity. Empirical data are used to demonstrate the application of the proposed model for decision making. In addition to construction and maintenance costs, and user costs, decisions are shown to be sensitive to the level of uncertainty of design year enplanements.
A Methodology for estimating traffic safety improvements at intersections
Authors: Ben‐Akiva M. , Ceder A. , Cheng L‐H. , Liss C. M.
Published: January 2010

Intersection accidents represent a significant proportion of overall motor vehicle accidents. More accurate estimates of the actual effectiveness of intersection safety improvements are required.

This study develops an improved methodology for post‐implementation evaluation of safety countermeasures at intersections. Accidents are random, rarely occurring events. For a given time period, this leads to random fluctuations in accident frequencies, which suggests that statistical analysis employing confidence intervals, rather than point estimates, is required. Two technical problems complicate this treatment of accident occurrence as a random variable. The first problem is that identifying of hazardous locations is generally based on above‐average accident frequency during the most recent period(s) for which data is available. The second problem arises from changes in external factors such as traffic volume, motor vehicle safety standards, etc., during the period of analysis, which may also affect traffic safety.

A “combined” approach which addresses these technical issues is developed. Empirical Bayesian methodology is combined with regression techniques to derive a more accurate measure of the effect of safety treatments. An important consideration is the derivation of the variance of this measure, so that appropriate confidence intervals may be constructed. The approach is then applied to a sample of locations that underwent treatment by the Massachusetts Department of Public Works (MDPW). We compare our results to those which might be obtained using alternative methodologies that correct for neither or only one of the technical problems. We also illustrate how preliminary conclusions may be drawn regarding the effectiveness of broad categories of treatments, and how individual sites requiring further investigation may be identified.
A schedule‐based time‐dependent trip assignment model for transit networks
Authors: Tong C. O. , Wong S. C.
Published: January 2010

A schedule‐based time‐dependent trip assignment model for transit networks is presented. First the transit network model is formulated using the schedule‐based approach, in which the vehicles are assumed to arrive punctually in accordance with a scheduled time‐table. Based on a previously developed time‐dependent shortest path algorithm, an all‐or‐nothing network loading procedure is employed to assign the passenger trips onto the network. Both the passenger demand and scheduled time‐table are time‐varying. This provides a versatile tool for the evaluation of the performance of transit networks subject to peak period loading. A case study using the Mass Transit Railway System in Hong Kong is given to illustrate the potential applications of the model.
An applicatoin of an optimal traffic control during lane closure periods of a two‐lane road
Authors: Ceder Avishai
Published: January 2010

On two‐lane roadways, when provision should be made for alternative one‐way movement (for construction or maintenance), the traffic characteristics differ from normal operation in which no lane is closed. The purpose of this study is to derive optimal strategies for controlling, by means of traffic signals, the one lane operation (in two‐way roadways). In this study, strategies to determine the optimal length of the closed one‐lane section during construction and maintenance work are established. This length minimizes the objective function representing the tradeoff between delay cost and operational cost. Using the length value obtained by the proposed model, plus a timing methodology, the overall cost of operating the closed highway section can be minimized. The sensitivity analysis of the optimal solution for the section length is examined with respect to the input variables. This analysis shows that for very low traffic flow values (less than 100 vph per direction), the solution is very sensitive to fuel price changes, while for greater flow values, the solution is insensitive to this change. Similar results are obtained for changes in the worker's wage which is part of both the operational and the delay cost. That is, the section's length is sensitive to wage changes at low traffic flow and insensitive otherwise. Based on the results presented in this study, it is possible to establish a guideline for the section's length determination. The control measure can emerge from a pair of traffic signals that can be installed at both ends of the closed highway segment. This traffic control system is also described in the study in terms of its components and operational features and advantages.
Estimation of AADT from short period counts in hong kong — A comparison between neural network method and regression analysis
Authors: Lam William H. K. , Xu Jianmin
Published: January 2010

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.
Estimating time dependent O‐D trip tables during peak periods
Authors: Pulugurtha Srinivas S. , Nambisan Shashi S.
Published: January 2010

Intelligent transportation systems (ITS) have been used to alleviate congestion problems arising due to demand during peak periods. The success of ITS strategies relies heavily on two factors: 1) the ability to accurately estimate the temporal and spatial distribution of travel demand on the transportation network during peak periods, and, 2) providing real‐time route guidance to users. This paper addresses the first factor. A model to estimate time dependent origin‐destination (O‐D) trip tables in urban areas during peak periods is proposed. The daily peak travel period is divided into several time slices to facilitate simulation and modeling. In urban areas, a majority of the trips during peak periods are work trips. For illustration purposes, only peak period work trips are considered in this paper. The proposed methodology is based on the arrival pattern of trips at a traffic analysis zone (TAZ) and the distribution of their travel times. The travel time matrix for the peak period, the O‐D trip table for the peak period, and the number of trips expected to arrive at each TAZ at different work start times are inputs to the model. The model outputs are O‐D trip tables for each time slice in the peak period. 1995 data for the Las Vegas metropolitan area are considered for testing and validating the model, and its application. The model is reasonably robust, but some lack of precision was observed. This is due to two possible reasons: 1) rounding‐off, and, 2) low ratio of total number of trips to total number of O‐D pair combinations. Hence, an attempt is made to study the effect of increasing this ratio on error estimates. The ratio is increased by multiplying each O‐D pair trip element with a scaling factor. Better estimates were obtained. Computational issues involved with the simulation and modeling process are discussed.
A bi‐level programming approach — Optimal transit fare under line capacity constraints
Authors: Zhou Jing , Lam William H. K.
Published: January 2010

The fare of a transit line is one of the important decision variables for transit network design. It has been advocated as an efficient means of coordinating the transit passenger flows and of alleviating congestion in the transit network. This paper shows how transit fare can be optimized so as to balance the passenger flow on the transit network and to reduce the overload delays of passengers at transit stops. A bi‐level programming method is developed to optimize the transit fare under line capacity constraints. The upper‐level problem seeks to minimize the total network travel time, while the lower‐level problem is a stochastic user equilibrium transit assignment model with line capacity constraints. A heuristic solution algorithm based on sensitivity analysis is proposed. Numerical example is used to illustrate the application of the proposed model and solution algorithm.
Bus routing strategies in a transit market: A case study of Hong Kong
Authors: Wang James J. , Po Karen
Published: January 2010

Conventionally, the objective of transit routing is often set either to minimize the total operational cost, subject to a given level of service quality, or to maximize the service quality at a given acceptable cost. In a deregulated, commercial‐based environment however, such as bus and railway operations in cities of the UK and Hong Kong where several private firms compete in route‐based or area‐based market, routing becomes one of the means for higher returns rather than just for cost saving. In such a case, how do the transit providers set up their routes for profit‐maximization? Will the routing based on the provider's objective meet the user's objective? How do government regulations and policies affect the choice of transit provider's routing strategy?

To answer these questions, we first examine the relationship between the objectives of users and transit providers, set up criteria for transit routing quality, and then investigate the possible routing configurations/patterns for a hypothetical case. These criteria include (1) the load factor of transit, (2) the level of route directness, (3) the level of route overlapping, and (4) the total number of routes and (5) the average of route length. These measures are finally applied to a real case in Hong Kong to examine the route changes of Kowloon Motor Bus from 1975 to 1995. The result of the empirical case reveais how key measures such as load factor are controlled by the bus operator and affected by government policies and how the bus routing pattern was adjusted to meet users' need. Facing the dilemma as evident in Hong Kong between the route directness and the efficiency of road use, we suggest that a rational multi‐modal routing structure be put in place if an institutional solution is introduced so that bus and other transit modes can form a sharing program or an alliance.