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Civil infrastructure managers have a profound interest in knowing the costs of infrastructure degradation caused by user operations that exceed statutory limits; that way, they are better informed to establish or revise policies related to permit fee structures for such extra-legal operations. In the specific context of vehicle weight permitting for highway bridges, past determinations have typically relied largely on bridge damage simulation using theoretical relationships between the loading and failure modes. Unlike the theory-based simulations, empirical data analysis uses observed field data and therefore are expected to yield more intuitive insights about the actual relationship between in-service loading patterns and their damage (and the cost of repair thereof). A few past studies have used such empirical approaches with some success but have generally been stymied by practical considerations including the lack of adequate translational relationships between the vehicles operating on the road and the vehicle classes typically considered in load analysis. Also, the overweight (OW) cost differences across different bridges attributes (material type, design type, functional class, and age) remain to be investigated. In a bid to overcome these limitations, this paper uses observed in-service data for vehicle loads and the life-cycle costs associated with bridge deterioration repair. The proposed methodology includes a technique that correlates AASHTO design vehicles to FHWA vehicle classes, estimates the total life-cycle cost of bridge upkeep, and allocates this cost to each user group (vehicle class) based on the axle configuration and usage frequency (vehicle-miles travelled) of that class. For each vehicle class, the marginal cost of bridge damage is determined on the basis of the incremental cost responsibility (as a result of adding that vehicle class to the traffic stream) and the typical traffic volume of that vehicle class, and were found to range from $0.01 to as much as $36.35 per ft. length per pass of bridge, depending on OW class, and bridge functional class, material type, and age. The paper quantifies the extent to which bridge damage cost due to an overweight truck is influenced by the attributes of the truck and the bridge. The results can be of help to agencies seeking to formulate, update, or evaluate current or future OW permitting policies from the perspective of highway bridge damage among other impacts. This effort is considered timely in the current era when several highway agencies are considering relaxation of their OW permitting policies as a part of efforts to project a business-friendly image in a bid to spur economic development in their states. [ABSTRACT FROM AUTHOR]

Abstract This paper shows that automated driving can lead both, to growth and decline of cities. We simulate spatial effects of automated driving for the Netherlands using LUCA, the Dutch spatial general equilibrium model. Two components of automation are accounted for: (i) more productive time use during car trips; (ii) fast and comfortable door-to-door automated public transit. We find that the car component results in population flight from cities, while the public transit component leads to population clustering in urban areas. A combination of the two may result in the population concentrating in the largest, most attractive cities, at the expense of smaller cities and non-urban regions. The simulations suggest that welfare benefits of automation are considerable, with up to 10% coming from population relocation and changes in land use. Our results are particularly relevant for countries where public transit claims a considerable share of urban mobility. Neglecting the impact of vehicle automation on public transit could result in biased policy recommendations. [ABSTRACT FROM AUTHOR]

This paper proposes and simulates an integrated autonomous vehicle (AV) and public transportation (PT) system. After discussing the attributes of and the interaction among the prospective stakeholders in the system, we identify opportunities for synergy between AVs and the PT system based on Singapore’s organizational structure and demand characteristics. Envisioning an integrated system in the context of the first-mile problem during morning peak hours, we propose to preserve high demand bus routes while repurposing low-demand bus routes and using shared AVs as an alternative. An agent-based supply-side simulation is built to assess the performance of the proposed service in fifty-two scenarios with different fleet sizes and ridesharing preferences. Under a set of assumptions on AV operation costs and dispatching algorithms, the results show that the integrated system has the potential of enhancing service quality, occupying fewer road resources, being financially sustainable, and utilizing bus services more efficiently. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a dynamic nearest neighbor (DNN) policy is proposed for operating a fleet of vehicles to serve customers, who place calls in a Euclidean service area according to a Poisson process. Each vehicle serves one customer at a time, who has a distinct origin and destination independently and uniformly distributed within the service area. The new DNN policy is a refined version of the nearest neighbor (NN) policy that is well known to perform sub-optimally when the frequency of customer requests is high. The DNN policy maintains geographically closest customer-to-vehicle assignments, due to its ability to divert/re-assign vehicles that may be already en-route to pick up other customers, when another vehicle becomes available or a new customer call arrives. Two other pertinent issues addressed include: the pro-active deployment of the vehicles by anticipating in which regions of the service area future calls are more likely to arise; and, imposition of limits to avoid prohibitively long customer wait times. The paper also presents accurate approximations for all the policies compared. Extensive simulations, some of which are included herein, clearly show the DNN policy to be tangibly superior to the first-come-first-served (FCFS) and NN policies. [Copyright &y& Elsevier]

The state of the art approach to economic consequence analysis (ECA) is computable general equilibrium (CGE) modeling. However, such models contain thousands of equations and cannot readily be incorporated into computerized systems to yield rapid estimates of economic impacts of various types of transportation system failures due to natural hazards, terrorist attacks or technological accidents. This paper presents a reduced-form approach to simplify the analytical content of CGE models and make them more transparent and enhance their utilization potential. The reduced-form CGE analysis is conducted by first running simulations one hundred times, varying key parameters, such as the magnitude of the initial shock, duration, location, behavioral responses, and resilience, according to a Latin Hypercube sampling procedure. Statistical analysis is then applied to the “synthetic data” results in the form of both ordinary least-squares and quantile regression. The analysis yields linear equations that are incorporated into a computerized system and utilized along with Monte Carlo simulation methods for propagating uncertainties in economic consequences. Although our demonstration and discussion focuses on aviation system disruptions caused by terrorist attacks, the approach can be applied to a broad range of threat scenarios. [ABSTRACT FROM AUTHOR]

There are natural synergies between shared autonomous vehicle (AV) fleets and electric vehicle (EV) technology, since fleets of AVs resolve the practical limitations of today’s non-autonomous EVs, including traveler range anxiety, access to charging infrastructure, and charging time management. Fleet-managed AVs relieve such concerns, managing range and charging activities based on real-time trip demand and established charging-station locations, as demonstrated in this paper. This work explores the management of a fleet of shared autonomous electric vehicles (SAEVs) in a regional, discrete-time, agent-based model. The simulation examines the operation of SAEVs under various vehicle range and charging infrastructure scenarios in a gridded city modeled roughly after the densities of Austin, Texas. Results based on 2009 NHTS trip distance and time-of-day distributions indicate that fleet size is sensitive to battery recharge time and vehicle range, with each 80-mile range SAEV replacing 3.7 privately owned vehicles and each 200-mile range SAEV replacing 5.5 privately owned vehicles, under Level II (240-volt AC) charging. With Level III 480-volt DC fast-charging infrastructure in place, these ratios rise to 5.4 vehicles for the 80-mile range SAEV and 6.8 vehicles for the 200-mile range SAEV. SAEVs can serve 96–98% of trip requests with average wait times between 7 and 10 minutes per trip. However, due to the need to travel while “empty” for charging and passenger pick-up, SAEV fleets are predicted to generate an additional 7.1–14.0% of travel miles. Financial analysis suggests that the combined cost of charging infrastructure, vehicle capital and maintenance, electricity, insurance, and registration for a fleet of SAEVs ranges from $0.42 to $0.49 per occupied mile traveled, which implies SAEV service can be offered at the equivalent per-mile cost of private vehicle ownership for low-mileage households, and thus be competitive with current manually-driven carsharing services and significantly cheaper than on-demand driver-operated transportation services. When Austin-specific trip patterns (with more concentrated trip origins and destinations) are introduced in a final case study, the simulation predicts a decrease in fleet “empty” vehicle-miles (down to 3–4% of all SAEV travel) and average wait times (ranging from 2 to 4 minutes per trip), with each SAEV replacing 5–9 privately owned vehicles. [ABSTRACT FROM AUTHOR]

Abstract: Climate change is a global problem and across the world the transport sector is finding it difficult to break projected increases in carbon dioxide (CO2) emissions; there are very few contexts where deep reductions in transport CO2 emissions are being made. A number of research studies are now examining the potential for future lower CO2 emissions in the transport sector. This paper develops this work to consider some of the wider sustainability impacts (economic, social and local environmental) as well as the lower CO2 transport impacts of different policy trajectories. Hence the central argument made is for an integrated approach to transport policy making over the longer term – incorporating scenario analysis and multi-criteria assessment (MCA) – to help assess likely progress against a range of objectives. The analysis is based on work carried out in Oxfordshire, UK. Different packages of measures are selected and two scenarios developed which satisfy lower CO2 aspirations, one of which also provides wider positive sustainability impacts. A simulation model has been produced to help explore the strategic policy choices and tensions evident for decision-makers involved in local transport planning. The paper argues for a ‘strategic conversation’ () at the sub-regional and city level, based upon future scenario analysis and MCA, discussing the priorities for intervention. Such an approach will help us examine the scale of change and trade-offs required in moving towards sustainable transport futures. [Copyright &y& Elsevier]

Abstract: Traffic Management Centers play a vital role in efficient functioning of freeway network in the post-incident scenario. As per present practice in Korea, the traffic managers use a heuristic approach for incident analysis based on their experience of similar scenarios. However, this approach induces uncertainty thereby reducing the overall effectiveness of the subsequent incident management and rescue operations. This paper proposes a decision support system to account for these shortcomings. We name our system as ‘FIAS’ – Freeway Incident Analysis System. The novel idea presented in this paper is the use of historical, real-time and spatial data simultaneously to forecast post-incident traffic flows on a microscopic simulation platform, Cellular Automata. FIAS incorporate two additional rules in the conventional model to depict more realistic incident flow characteristics. This paper focuses on the system architecture of the model and tests its performance by comparing its predicted values with a real incident data. The evaluation results confirm the validity of FIAS as it can model the time dependent microstructure of traffic flows with significant accuracy. [Copyright &y& Elsevier]

Abstract: Traffic simulation models make assumptions about the safety-related behaviour of drivers. These assumptions may or may not replicate the real behaviour of those drivers who adopt seemingly unsafe behaviour, for example running red lights at signalised intersections or too closely following the vehicles in front. Such behaviour results in the performance of the system that we observe but will often result in conflicts and very occasionally in accidents. The question is whether these models should reflect safe behaviour or actual behaviour. Good design should seek to enhance safety, but is the safety of a design necessarily enhanced by making unrealistically optimistic assumptions about the safety of drivers’ behaviour? This paper explores the questions associated with the choice of values for safety-related parameters in simulation models. The paper identifies the key parameters of traffic simulation models and notes that several of them have been derived from theory or informed guesswork rather than observation of real behaviour and that, even where they are based on observations, these may have been conducted in circumstances quite different to those which now apply. Tests with the micro-simulation model DRACULA demonstrate the sensitivity of model predictions—and perhaps policy decisions—to the value of some of the key parameters. It is concluded that, in general, it is better to use values that are realistic-but-unsafe than values that are safe-but-unrealistic. Although the use of realistic-but-unsafe parameter values could result in the adoption of unsafe designs, this problem can be overcome by paying attention to the safety aspects of designs. The possibility of using traffic simulation models to produce estimates of accident potential and the difficulties involved in doing so are discussed. [Copyright &y& Elsevier]

This paper presents a hybrid simulation-assignment modeling framework for studying crowd dynamics in large-scale pedestrian facilities. The proposed modeling framework judiciously manages the trade-off between ability to accurately capture congestion phenomena resulting from the pedestrians’ collective behavior and scalability to model large facilities. We present a novel modeling framework that integrates a dynamic simulation-assignment logic with a hybrid (two-layer or bi-resolution) representation of the facility. The top layer consists of a network representation of the facility, which enables modeling the pedestrians’ route planning decisions while performing their activities. The bottom layer consists of a high resolution Cellular Automata (CA) system for all open spaces, which enables modeling the pedestrians’ local maneuvers and movement decisions at a high level of detail. The model is applied to simulate the crowd dynamics in the ground floor of Al-Haram Al-Sharif Mosque in the City of Mecca, Saudi Arabia during the pilgrimage season. The analysis illustrates the model’s capability in accurately representing the observed congestion phenomena in the facility. [ABSTRACT FROM AUTHOR]

Control strategies that prevent bus bunching allow for improvement to the level of service offered by a transit corridor as well as reducing travel time and its variability, thus providing higher reliability to the user. Several optimization models based on the use of real-time information have been shown to achieve this, through the planning of holding of the buses at bus stops. In the majority of the cases the benefits of these models have been estimated assuming ideal operational conditions while only few of them have been tested in real conditions. However, neither the simulation experiment, nor the real implementations have quantified the effects of real-life phenomena that harm the performance of the system, preventing it from achieving the full potential of these control schemes. This paper examines three phenomena that may occur during the operation of a bus service, which would limit the effectiveness of a holding-based control strategy in the sense that some of the planned holdings might not be executed. These phenomena are drivers non-compliance, failure of communication systems with buses, and the combination of both. The objective is to estimate the negative impact these phenomena can have on the benefits of the strategy, and to identify possible measures that could help operators and decision makers to reduce this impact. Both objectives are achieved using the real-time holding model developed by Delgado et al. (2012), which is tested in a simulation environment. [ABSTRACT FROM AUTHOR]

The LAX North Airfield Safety Study was undertaken by an Academic Panel consisting of the present authors, and was based in large part on a simulation that was conducted at FutureFlight Central at NASA Ames Research Center. The primary aim of the study was “to estimate as specifically as possible the level of future safety associated with several geometrical configurations of the LAX North Airfield.” This paper describes the study, and how it combined information from human-in-the-loop simulations at NASA with historical data from LAX and other US airports about runway incursions and collisions. The analysis indicated that, even under its existing physical layout, LAX North would experience very low risk of runway collisions at traffic levels projected for 2020. That risk could be reduced by about half if the North Airfield runways were reconfigured, and some reconfigurations would also add appreciably to the operational efficiency of the airport. But because the “baseline” level of risk is so low, the Study concluded that “it would be difficult to construct a compelling case on safety grounds alone for reconfiguring the North Airfield.” [ABSTRACT FROM AUTHOR]

Abstract: This paper develops a novel agent-based transportation model of a university campus, primarily focusing on vehicle-related travel and the associated parking search process. In developing and validating the model, the study uses a wide range of data sources including: (1) a brief “trip-diary” type survey; (2) 24-h traffic counts at the entry and exit points to the campus; (3) information about the university buildings’ class room capacities and class schedules; (4) parking occupancy surveys; and (5) select intersections’ turn movement counts. The agent-based model is designed to explicitly capture trip chaining behavior, and the often-overlooked phenomenon of drivers searching for an available parking spot. The parking search process is modeled using a sequential game-theoretic, neo-additive capacity model which accounts for drivers optimistic and pessimistic attitudes regarding parking availability in their most desirable lot. The agent-based demand model is then integrated with the Transportation Analysis and Simulation System (TRANSIMS), which serves as the traffic micro-simulation engine, and with the MOVES2010 emissions model. Following the validation of the integrated model, it is used to quantify the environmental cost of the parking search process on campus. The study may be regarded as one of the few studies to integrate an agent- or activity based model of travel demand, albeit admittedly simplified, with a fine-grained transportation network, a detailed traffic micro-simulation, and a project-level emissions model. Another contribution of the study is in terms of quantifying the environmental cost, in terms of wasted fuel and increased emissions, associated with the parking search process on campus. [Copyright &y& Elsevier]

Abstract: The system considered is a cinema ticketing booth system. A general simulation algorithm is presented as well as the system’s operating characteristics. The results of the experiment were verified by comparing them with video observation data and theoretical values. Finally, with comparative analysis of experiment data, the developed simulation model was able to replicate the situation in which pedestrians find an available booth to occupy while waiting in a queue. The model can facilitate the availability of various pedestrian flows and a range of operating times. With some efforts of computer programming, the situations where multiple booths are available were simulated to identify pedestrian movement. The developed simulation model captures important details, such as travel time, wait time, queue length and the number of waiting pedestrians with the different number of pedestrian flows and booths. The paper presents a means to designing the pedestrian operation and plan on the basis of the estimated number of people. [Copyright &y& Elsevier]

Abstract: The use of Multinomial Logit (MNL) models specification for the simulation of residential location have been often criticised due to the Independence of Irrelevant Alternatives hypothesis (IIA) which does not allow for the existence of spatial correlation between residential zones. Moreover, it is not clear when and to what extent the influence of the workplace zone and accessibility to employment affect the residential location choices made by households; in other word, whether the residing choice is conditional to the workplace, or vice versa; or if such choices (residence and work place) are joint. In this paper, Nested Logit (NL) and Cross-Nested Logit models of residential location choice are specified and compared to MNL, to investigate the existence of spatial correlation between different locations. Furthermore, different assumptions are tested, considering the choice of residential zone and the joint choice of residential zone and work place zone. The models were estimated for the urban area of Santander (Spain). The results indicate that the inclusion in the model specification, of the spatial correlation between zones fit the data significantly better. Home-work journey times were a statistically significant factor in household location choice, whereas accessibility to employment had the correct sign but it was not statistically significant. [Copyright &y& Elsevier]

Abstract: Issues concerning the use of baby carriages in public buses are still pendant of international legislation that could contribute to unify provisions around accessibility and safety on this type of transportation. There is actually a lack of knowledge around the dynamic behavior and forces involved in the movement of baby carriages when on board in public transportation services. This paper focuses on an analysis of the forces transmitted to the baby carriages and their behavior during normal operation and critical maneuvers by public buses. The article presents partially the results obtained from a research project conducted by the Institute of Design and Manufacturing (IDF) of the Universitat Politècnica de València (Spain) in cooperation with the Institute for Automobile Research (INSIA) of the Universidad Politécnica de Madrid (Spain). The aim was to establish the technical requirements for accessibility and safety of baby carriages (US) or prams (UK) in public buses that could help national and international community to develop standards and provisions on this type of people mobility. A series of tests with different types of baby carriages were carried out in public transportation buses in closed tracks and open roads to simulate the behavior of critical maneuvers in urban traffic. From an analysis of the testing results it was possible to identify situations where restraint systems should be used, as well as the safest orientation and location within a bus for baby carriages, and enabled the development of a ‘Code of Good Practice’ for bus operators, users, and baby carriage manufacturers. Furthermore, the analysis of the dynamic forces allowed the development of a new restraint device for securing carriages inside the vehicle’s passenger compartment. [Copyright &y& Elsevier]

Abstract: The need for sustainable development is increasing as the industrial and service activities keep putting such a strain on the natural functions of the Earth, thus the ability of the planet’s to sustain future generations. Since most of the industrial and service activities are provided via transportation, it is one of the most crucial elements of sustainable development. In this paper, US highway system sustainability problem is studied. System dynamics modeling approach is employed due to the causal relationships and feedback loops that are observed in the problem structure. The reference mode is considered as the increasing CO2 emission trend. The objective is to meet the Liberman and Warner Climate Act’s targets by 2050. Three potential strategies for policy making are tested with the developed dynamic simulation: fuel efficiency, public transportation and electric vehicle usage. The results indicate that hybrid implementation of individual policies has a crucial impact on the success of policy making. [Copyright &y& Elsevier]

Abstract: With increasing demand for air transportation worldwide and decreasing marginal fuel efficiency improvements, the contribution of aviation to climate change relative to other sectors is projected to increase in the future. As a result, growing public and political pressures are likely to further target air transportation to reduce its greenhouse gas emissions. The key challenges faced by policy makers and air transportation industry stakeholders is to reduce aviation greenhouse gas emissions while sustaining mobility for passengers and time-sensitive cargo as well as meeting future demand for air transportation in developing and emerging countries. This paper examines five generic policies for reducing the emissions of commercial aviation; (1) technological efficiency improvements, (2) operational efficiency improvements, (3) use of alternative fuels, (4) demand shift and (5) carbon pricing (i.e. market-based incentives). In order to evaluate the impacts of these policies on total emissions, air transport mobility, airfares and airline profitability, a system dynamics modeling approach was used. The Global Aviation Industry Dynamics (GAID) model captures the systemic interactions and the delayed feedbacks in the air transportation system and allows scenarios testing through simulations. For this analysis, a set of 34 scenarios with various levels of aggressiveness along the five generic policies were simulated and tested. It was found that no single policy can maintain emissions levels steady while increasing projected demand for air transportation. Simulation results suggest that a combination of the proposed policies does produce results that are close to a “weak” sustainability definition of increasing supply to meet new demand needs while maintaining constant or increasing slightly emissions levels. A combination of policies that includes aggressive levels of technological and operations efficiency improvements, use of biofuels along with moderate levels of carbon pricing and short-haul demand shifts efforts achieves a 140% increase in capacity in 2024 over 2004 while only increasing emissions by 20% over 2004. In addition, airline profitability is moderately impacted (10% reduction) compared to other scenarios where profitability is reduced by over 50% which pose a threat to necessary investments and the implementation of mitigating measures to reduce CO2 emissions. This study has shown that an approach based on a portfolio of mitigating measures and policies spanning across technology and operational improvements, use of biofuels, demand shift and carbon pricing is required to transition the air transportation industry close to an operating point of environmental and mobility sustainability. [Copyright &y& Elsevier]

Abstract: This paper presents and tests a method to design high-performance transit networks. The method produces conceptual plans for geometric idealizations of a particular city that are later adapted to the real conditions. These conceptual plans are generalizations of the hybrid network concept proposed in . The best plan for a specific application is chosen via optimization. The objective function is composed of analytic formulae for a concept’s agency cost and user level of service. These formulae include as parameters key demand-side attributes of the city, assumed to be rectangular, and supply-side attributes of the transit technology. They also include as decision variables the system’s line and stop spacings, the degree to which it focuses passenger trips on the city center, and the service headway. These decision variables are sufficient to define an idealized geometric layout of the system and an operating plan. This layout-operating plan is then used as a design target when developing the real, detailed master plan. Ultimately, the latter is simulated to obtain more accurate cost and level of service estimates. This process has been applied to design a high performance bus (HPB) network for Barcelona (Spain). The idealized solution for Barcelona includes 182km of one-way infrastructure, uses 250 vehicles and costs 42,489€/h to build and run. These figures only amount to about one third of the agency resources and cost currently used to provide bus service. A detailed design that resembles this target and conforms to the peculiarities of the city is also presented and simulated. The agency cost and user level of service metrics of the simulated system differ from those of the idealized model by less than 10%. Although the designed and simulated HPB systems provide sub-optimal spatial coverage because Barcelona lacks suitable streets, the level of service is good. Simulations suggest that if the proposed system was implemented side-by-side with the current one, it would capture most of the demand. [Copyright &y& Elsevier]

Abstract: As of November 2008, the number of cell phone subscribers in the US exceeded 267 million, nearly three times more than the 97 million subscribers in June 2000. This rapid growth in cell phone use has led to concerns regarding their impact on driver performance and road safety. Numerous legislative efforts are under way to restrict hand-held cell phone use while driving. Since 1999, every state has considered such legislation, but few have passed primary enforcement laws. As of 2008, six states, the District of Columbia (DC), and the Virgin Islands have laws banning the use of hand-held cell phones while driving. A review of the literature suggests that in laboratory settings, hand-held cell phone use impairs driver performance by increasing tension, delaying reaction time, and decreasing awareness. However, there exists insufficient evidence to prove that hand-held cell phone use increases automobile-accident-risk. In contrast to other research in this area that uses questionnaires, tests, and simulators, this study analyzes the impact of hand-held cell phone use on driving safety based on historical automobile-accident-risk-related data and statistics, which would be of interest to transportation policy-makers. To this end, a pre-law and post-law comparison of automobile accident rate measures provides one way to assess the effect of hand-held cell phone bans on driving safety; this paper provides such an analysis using public domain data sources. A discussion of what additional data are required to build convincing arguments in support of or against legislation is also provided. [Copyright &y& Elsevier]

Abstract: External station travel surveys provide critical inputs to travel demand models. The results from these models are frequently used for statewide planning purposes. Although a roadside survey is very effective in obtaining useful information from road users, its major drawback is the excessive delay that is imposed onto road users particularly on high-volume facilities. In this paper, we used a discrete event simulation to model a blocked traffic lane survey, which is usually conducted for two-lane undivided highways. This type of survey station requires a complete stop of all oncoming traffic. Non-surveyed traffic has no ability to go around and thus has to wait in a queue in order to proceed through the survey station. Road users’ impacts are quantified in terms of delay and queue length while the performance of surveyors is measured by the number of surveys completed per unit time. Sensitivity analyses of simulation inputs reveal that simulation results are fairly insensitive to selected parameters. The results in this study provide a quick and useful guideline that roadside surveyors can use to estimate the road user impacts prior to the survey and to plan the survey procedure accordingly. [Copyright &y& Elsevier]

Abstract: Assessment of unfair competitive practices in airline markets has traditionally been based on the analysis of changes in average fares, revenue and traffic following low-fare entry. This paper demonstrates the severe limitations of using such measures. In particular, our case studies show that despite very different perceptions by some analysts of apparent incumbent carrier response to entry, average fares, revenues and traffic measures showed very similar patterns of change. We then use a competitive airline market simulation to illustrate the importance of often ignored factors – revenue management and the flows of connecting network passengers on the flight legs affected by low-fare entry – in explaining the effects of entry on these aggregate measures of airline performance. These simulation results further reinforce the danger in using such measures as indicators of predatory behavior in airline markets. [Copyright &y& Elsevier]

Abstract: This paper develops a new agent-based simulation model to improve discrete choice analysis as well as to analyse the effects of a road user charging scheme for the Upper Derwent Valley in the Peak District National Park. The advantages of discrete choice analysis are well known. However, results with these conventional methods can be biased if interaction effects are significant. The combined approach of the Minority Game, in which agents try to choose the option of the minority side, and discrete choice analysis is appropriate to deal with the problem. The main data was collected by stated preference survey. The agent-based model has four sub-modules: (1) multinomial mixed logit model for mode choice, (2) binary logit model for parking location choice, (3) Markov queue model for parking network, and (4) the Minority Game for parking congestion and learning. The results show that the road user charging scheme reduces car demand in the Upper Derwent Valley. The model also shows that an exemption will increase the utility of elderly visitors. In conclusion, the simulation model demonstrated that oversimplification in conventional discrete choice analysis gave significant biases when real world problems were analysed. [Copyright &y& Elsevier]

Abstract: In this paper we study the impact on productivity of specific operating practices currently used by demand responsive transit (DRT) providers. We investigate the effect of using a zoning vs. a no-zoning strategy and time-window settings on performance measures such as total trip miles, deadhead miles and fleet size. It is difficult to establish closed-form expressions to assess the impact on the performance measures of a specific zoning practice or time-window setting for a real transportation network. Thus, we conduct this study through a simulation model of the operations of DRT providers on a network based on data for DRT service in Los Angeles County. However, the methodology is quite general and applicable to any other service area. Our results suggest the existence of linear relationships between operating practices and performance measures. In particular we observe that for each minute increase in time-window size the service saves approximately 2 vehicles and 260 miles driven and that a no-zoning strategy is able to satisfy the same demand by employing 60 less vehicles and driving 10,000 less total miles with respect to the current zoning strategy. [Copyright &y& Elsevier]

Abstract: Transportation, energy and environmental tax reforms represent an ongoing debate in contemporary policy. The main aim of this paper is to shed some light on this debate using micro-simulation tools to analyse consumer response and welfare effects of environmental policy consisting of an increment of the indirect taxes on fuels to finance the elimination of VAT on the public means of transport. In order to do so, we first estimate an Almost Ideal Demand System for 16 different groups of goods in the Spanish economy, for the purpose of evaluating expenditure and price elasticities. Using this information, we then micro-simulate the abolition of VAT on public transport services and a simultaneous increment on fuel taxes, so that total revenue remains unchanged. The welfare effects of this revenue-neutral tax reform are evaluated. The aim of this simulation is to define a public policy that increases public transportation availability and use in order to bring about decreases in pollution and congestion. [Copyright &y& Elsevier]

Abstract: There has been rapid growth in interest in real-time transport strategies over the last decade, ranging from automated highway systems and responsive traffic signal control to incident management and driver information systems. The complexity of these strategies, in terms of the spatial and temporal interactions within the transport system, has led to a parallel growth in the application of traffic microsimulation models for the evaluation and design of such measures, as a remedy to the limitations faced by conventional static, macroscopic approaches. However, while this naturally addresses the immediate impacts of the measure, a difficulty that remains is the question of how the secondary impacts, specifically the effect on route and departure time choice of subsequent trips, may be handled in a consistent manner within a microsimulation framework. The paper describes a modelling approach to road network traffic, in which the emphasis is on the integrated microsimulation of individual trip-makers’ decisions and individual vehicle movements across the network. To achieve this it represents directly individual drivers’ choices and experiences as they evolve from day-to-day, combined with a detailed within-day traffic simulation model of the space–time trajectories of individual vehicles according to car-following and lane-changing rules and intersection regulations. It therefore models both day-to-day and within-day variability in both demand and supply conditions, and so, we believe, is particularly suited for the realistic modelling of real-time strategies such as those listed above. The full model specification is given, along with details of its algorithmic implementation. A number of representative numerical applications are presented, including: sensitivity studies of the impact of day-to-day variability; an application to the evaluation of alternative signal control policies; and the evaluation of the introduction of bus-only lanes in a sub-network of Leeds. Our experience demonstrates that this modelling framework is computationally feasible as a method for providing a fully internally consistent, microscopic, dynamic assignment, incorporating both within- and between-day demand and supply dynamics. [Copyright &y& Elsevier]

Abstract: The gradually accelerating pace at which tolls are being implemented or actively considered around the world suggests that road pricing is an idea whose time may finally have come. Nevertheless, various design considerations must be addressed and public acceptability hurdles overcome if road pricing is to become widespread. And to measure the efficiency gains and welfare-distributional effects of road pricing accurately, models need to account for potential behavioural responses to tolls—and in particular adjustments in trip timing. This paper analyzes some road pricing schemes using the dynamic network simulator METROPOLIS: a tool that treats endogenously departure-time decisions as well as mode and route choices of individual travelers. Simulations are conducted for a stylized urban road network that consists of radial arterials and circumferential ring roads, and with trip origins and destinations that are distributed throughout the network. Six types of link-tolling schemes are analyzed: (1) the system optimum which can be supported approximately by imposing time-varying step tolls that eliminate queuing, (2) a set of comprehensive flat (time-independent) tolls, (3,4) second-best flat and step tolls for a toll cordon, and (5,6) second-best flat and step tolls within a charge area. Two results show the superiority of step tolls over flat tolls. First, step tolls easily outperform flat tolls in terms of welfare gains while inducing a smaller shift of trips from auto to transit. Second, step tolls generate smaller revenues than do flat tolls, and consequently have more favourable distributional impacts on travelers. [Copyright &y& Elsevier]