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This research reaffirms a sustainable transport investment should go forward in a way that enforces consistent economic growth while maintaining environmental benefit. Society's economic input-output relations reinvest the time saved by the transport system, of which benefit appeared as the income level's rise. This research empirically proves that the recursive profit is possible when the infrastructure aligns accessibility enhancement with industries' productivities. Specifically, we found that the interactions between industries and accessibilities make synergy when the industries maintain appropriate productivity. Under the same context, the measure for the socially vulnerable should start at capacity building even given transport, based on which we can build economically equitable accessibility. This research takes environmental sustainability granted as long as the incumbent Korean infrastructure investment principle exists without empirical analysis. A comparative analysis using structural equation models proved the existence of the synergy due to the accessibility-industry interactions. Besides, we captured the quantities of the synergy through groups of partial cross-sectional correlations. Authors conclude that government authority needs to pursue the best synergy between transport plan and economic development strategy, and prepare a capacity building for the socially vulnerable furthermore. [ABSTRACT FROM AUTHOR]

Most walking travel behavior research thus far has tested area-based neighborhood walkability, which is measured with meso-level urban form attributes. In need of micro-level walkability analyses that focus on individual travelers and their routes, we propose a route-oriented linear walkability concept named “path walkability.” It is defined and measured by 42 path walkability indicators that can collectively represent an individual traveler's micro-level walkability. A graphic measurement instrument for an objective and efficient on-field walkability measurement is developed. This study also sets the protocol for quantitatively integrating the walkability data measured at the segment level into path walkability indicators that are comparable at the route level. To test the applicability of the proposed path walkability, a pilot case study is conducted within a station area. A user survey is administered to collect transit users' access mode choices and walking routes to the station. The survey results help identify two groups of street segments: one used by regular walkers and the other selected by habitual auto users/occasional walkers. The routes chosen by the two groups are quantitatively and graphically compared for walkability. The analyses show a physically measurable and quantitatively comparable difference between the routes' walkability and suggest criteria for walking-conducive transit walkability for station users. Specific design recommendations for improving street-level micro-walkability for future transit-oriented developments (TODs) are added along with a future research agenda. [ABSTRACT FROM AUTHOR]

The public bike system (PBS) has been actively promoted worldwide for the last decade. This study tried to find out policy strategies for sustainable PBS implementation targeting on the city that is under consideration of introducing bike sharing scheme. For this, the authors considered some psychological factors that may make impacts on PBS user's attitudes and hypothesized especially that individual environmental concern refers to an attitude toward environmental issues, influence an increase of their perceived value of PBS. The Norm Activation Model (NAM) is used to measure the public's environmental concern incorporating norm activation. In addition, willingness to pay (WTP) method is adopted to investigate the value of PBS individuals. Structural equation modeling (SEM) revealed that environmental concern influenced people's perception of the value of PBS. Furthermore, the positive correlation between environmental concern and awareness of consequences on cycling is observed. The study verifies how people perceive the value of a bike sharing system and how often people using a bicycle are dependent on their environmental concern. In conclusion, authors discuss how PBS could be promoted sustainably by suggesting policy strategies to enhance the perceived value of PBS and to increase bicycle use. [ABSTRACT FROM AUTHOR]

In order to improve the effectiveness of transit-oriented development (TOD), the integration of public transportation and bikes has been regarded as a good alternative because the catchment area of a station, that is, the spatial extent of TOD, can be increased. This paper suggests the concept of bicycle-based TOD (B-TOD) and estimates the spatial extent, considering the catchment area. For this, a trip survey was conducted among bicycle users who used bicycle and public transportation in Seoul metropolitan and Daejeon metropolitan areas in Korea. Regression and cumulative distribution models were used to estimate the spatial extent of B-TOD. The results show that the estimated access distances were 1.96 km and 2.13 km for origin (home)-to-station and station-to-work trips, respectively, and they can play a yardstick role in the TOD planning practices in Korea. In such cases, the catchment areas of B-TOD cover 73.7% and 93.6% of the whole area of Seoul, whereas conventional walking-only TOD can cover only 29.9% of the same. This implies that B-TOD can help to solve one of the key inherent weaknesses of the conventional TOD. Some limitations and recommendations for future research are also discussed. [ABSTRACT FROM AUTHOR]

This article focuses on micro-level walkability, which is measured at the route level and thus named “path walkability,” and tests whether path walkability influences transit users' mode choices to the station. To test its impact on access mode choices, a case study is conducted in downtown Mountain View, California. A station user survey is administered to collect access mode choice, socioeconomic status, and trip origins and walking routes of 249 transit users with previous experience of walking to the station. Using a path walkability measurement instrument developed for this research, 38 path walkability indicators are extracted from each of the 249 walking routes. The 38 walkability indicators are grouped by using factor analysis yielding four path walkability factors: “sidewalk amenities,” “traffic impacts,” “street scale and enclosure,” and “landscaping elements.” The four factors are utilized as new walkability variables for modeling access mode choices. With 150 walkers and 99 habitual auto users/occasional walkers, two access mode choice models are estimated. The basic model is first estimated without walkability variables and then the four path walkability variables are introduced for the expanded model. All four path walkability variables enter the expanded model and significantly improve the predictability of the mode choice model. The model result suggests that micro-level walkability influences access mode choices in a statistically significant way and having more walking-conducive walkability available for access trips increases the chance of choosing walking over driving. This research shows that improving micro-level walkability could be a cost-beneficial incentive for more walking to the station. [ABSTRACT FROM PUBLISHER]

This study has dual research objectives: 1) to evaluate the land use characteristics of the pedestrian catchment areas (PCA) of subway stations in the Seoul metropolitan area (SMA) in terms of transit-oriented development (TOD) principles and 2) to investigate the influence of each PCA's land use characteristics on station-level ridership. The major findings can be summarized as follows. First, the built environments of subway PCAs in Seoul were found to be compatible with TOD principles in terms of density and diversity. They have declining density gradients of population and employment that extend outward from a station and have a high level of mixed-use land. Second, population and employment densities, land use mix diversity, and intermodal connectivity all have a positive impact on subway ridership, but differ in their spatial ranges. In particular, the influence spans of residential and commercial development patterns (population density and the proportion of commercial land) and mixed land use on ridership were limited to only the core and primary PCAs. Consequently, with respect to TOD in a compact city like Seoul, we recommend that a PCA be defined to encompass a radius of 600 m. [ABSTRACT FROM AUTHOR]

A nested logit model predicting the probabilities of commuters choosing three different modes were constructed to test the effect of the Seoul bus reform. Some empirical findings include the following. First, the Seoul BRT system contributed to increases in the patronage of bus over subway within the BRT catchment area (BCA). Second, commuters working in the BCA are more likely to choose to commute by bus than are people living in the BCA, which indicates that high accessibility to the BRT strongly influences workers who commute to their jobs to ride the bus. Third, percentage changes in the odds of choosing bus over subway were higher than those of choosing bus or subway over automobile for both BCAs, implying that the accessibility to the BRT contributed to inducing commuters to favor bus over subway. [ABSTRACT FROM AUTHOR]

As a progressive and open society, South Korea recognizes the importance of providing public services that respond to the needs of disadvantaged groups, reflecting principles of social justice and community inclusion. Korea has a growing foreign population, including many low-income migrant workers. This study investigates the transportation demands and problems of these workers, and identifies potential ways to better meet their travel needs. It is based on a survey of 300 randomly-selected Chinese, Vietnamese, Filipinos, Indonesian, and Thai workers living in Ansan, Buchon and Uijungbu industrial districts on the outskirts of the Seoul metropolitan region. The survey investigated respondents' ability to communicate in Korean, their knowledge of transportation services and traffic regulations, and their travel demands. Various transportation problems that these workers often face, and potential policy reforms to address these problems were identified. This study indicates that many new foreign workers could benefit from information resources and education programs on Korean language, transportation services, traffic rules and pedestrian safety. The topic is a relatively unexplored research subject; most previous research on low-income migrant population transport demands and improvement strategies is from European and North America. Some limitations and future research agenda have also been presented. [ABSTRACT FROM AUTHOR]

Highlights: [•] We model spatial regressions to examine the determinant factors of rail transit ridership. [•] Rail transit service coverage of 500m gives the best fit for estimating rail transit ridership levels. [•] Development density is positively associated with rail transit ridership within 750m service coverage. [•] Land use diversity does not show a significant association with rail transit ridership. [•] Station-level accessibility measures are the most important factors for promoting rail transit ridership. [Copyright &y& Elsevier]

The acceleration profile of leading vehicles at intersections is critical for emission estimation and microlevel queue simulation. Data obtained from experiments using a high-resolution driving simulator can deliver useful insights into microscale acceleration behaviors at signalized intersections. Acceleration data of the leading vehicles in queues are collected by the simulator. The observed accelerations are found to be stochastic. The acceleration characteristics are also significantly diversified among participants. Hence, a Markov chain is implemented to simulate the acceleration behaviors. The acceleration data are classified into varied operation states. And the Markov chain reconstructs the acceleration profiles of leading vehicles and reproduces the randomness of acceleration behaviors. Among numerous candidate profiles, a speed profile is selected by a proposed criterion that represents the typical acceleration behaviors at signalized intersections. [ABSTRACT FROM AUTHOR]

Although there are several policies for promoting green vehicles, green vehicles have yet to penetrate the market to the extent desired. To attain the goal, a complete understanding of consumers’ preferences of green vehicles is essential. This paper proposes and specifies the fuel-type choice models among conventional gasoline vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and electric vehicles by vehicle size using the stated preferences data collected in Seoul, Korea. The results highlight the need to accommodate the correlation between similar alternatives and the unobserved heterogeneity within the context of choosing a green vehicle. The choice probabilities of green vehicles are affected by the relative impacts of the vehicles’ attributes and socio-demographic variables, and both of these variables are affected by the sizes of the vehicles. For compact size and mid-size vehicles, the effects of operating costs were less than those of purchase prices; however, for the subcompact vehicles, the effects of operating cost were greater than those of purchase price. The parameter of operating costs was not statistically significant in the full-size model. With respect to electric vehicles, the availability of fuel stations would be more important in Seoul than in the U.S. These results can also be useful for policy makers in that they provide information about the impact of green vehicles’ attributes on the choice probabilities of green vehicles. [ABSTRACT FROM AUTHOR]

This study establishes a network data envelopment analysis (DEA) model to evaluate the sustainability of public transportation services targeting rapid routes for buses in the Seoul metropolitan area. A network DEA-based optimization model is formulated to evaluate the sustainability of the public transportation service. By considering public transportation services from both the operators’ and users’ perspectives, this model produces results that reflect the interaction of three sustainable transport service properties, i.e., efficiency, equity, and environmental impacts. It is identified that the expansion of median bus lanes and the conversion of conventional buses into compressed natural gas vehicles could improve the sustainability of the public transportation services in the Seoul metropolitan area. Some limitations and future research agenda also are presented. [ABSTRACT FROM PUBLISHER]

Transit-oriented development (TOD) has been recognized as an important avenue for creating a green transportation system. This paper addresses TOD investment issue in terms of the location, number and size of the TOD zones along a rail line. An urban system equilibrium problem with TOD investment is first formulated. Two social welfare maximization models, which take into account different investment regimes for TOD projects (i.e., public and private), are then proposed for optimizing TOD investment schemes along a rail line and train service frequency on that line. In the public regime model, the government is responsible for the investment cost of TOD projects, which is borne by the private property developers in the private regime model. The proposed models explicitly consider the interactions among the government, property developers and households in the urban system, together with the effects of the TOD investment on households’ residential location choices and housing market. The population thresholds for investing in a TOD project under the public and private regimes are also identified. The findings show that the TOD investment can cause population agglomeration at the TOD zones and a compact city; households and the society can benefit from the TOD investment; and the private TOD investment regime outperforms the public regime in terms of total social welfare of urban system. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are energy efficient and often presented as a zero-emission transport mode to achieve long-term decarbonization visions in the transport sector. The implementation of a sustainable transportation environment through EV utilization, however, requires the addressing of certain cost and environmental concerns such as limited driving range and battery-charging issues before its full potential can be realized. Nevertheless, a specific type of use of EVs, namely in taxi services, may elicit positive public opinion, as it promises a commitment toward sustainability in urban life. In light of this, this study proposes an integrated approach that combines EV operation with a conceptual design for shared-ride taxi services. As some productivity loss may be naturally expected due to the time spent in charging, it is important to look at whether such performance loss from the passenger and system standpoints can be offset with ingenuity in operational design. In this study, an EV taxi charge-replenishing scheme that can be coupled with a real-time taxi-dispatch algorithm is designed. The proposed EV charging schemes for taxi services are studied via simulations and the effects of the limited driving range and battery-charging details are examined from a system performance viewpoint. The simulation study also reveals illustrative results on the impact of the EV taxi fleet's operation on the charging system. Next, a real-time shared-taxi operation scheme that allows ride sharing with other passengers is proposed to maximize the operational efficiency. The simulation results suggest that the shared-taxi concept can be a viable option to improve on the limitations caused by EV operation. In addition, the importance of projected charging demands and queue delays at different charging locations are also addressed. Some limitations and a future research agenda are also discussed. [ABSTRACT FROM AUTHOR]

Today, air pollution is a great issue, and the transport sector is an important emission source. In this study, we present an integrated land use, transport, and environment model in which transport-related pollutants are assumed to influence people's housing location choices, and a continuum modeling approach is applied. The pollutants generated by the transport sector are dispersed by the wind and they affect air quality. The air quality changes people's housing choices, which in turn changes their travel behavior. We assume that the road users are continuously distributed over the city, that the road network is relatively dense, and that this network can be approximated as a continuum. The total demand is categorized into several classes, and the modeled region contains several subdistricts. People who live in different subdistricts or who belong to different classes of commuters are assumed to have different perceptions of travel time, air quality, and the housing provision–demand relationship. The finite element method and the Newton–Raphson algorithm are adopted to solve this problem, and a numerical valuation is given to illustrate the effectiveness and efficiency of the proposed model. [ABSTRACT FROM PUBLISHER]

Highway traffic accidents all over the world result in more than 1.3 million fatalities annually. An alarming number of these fatalities occurs in developing countries. There are many risk factors that are associated with frequent accidents, heavy loss of lives, and property damage in developing countries. Unfortunately, poor record keeping practices are very difficult obstacle to overcome in striving to obtain a near accurate casualty and safety data. In light of the fact that there are numerous accident causes, any attempts to curb the escalating death and injury rates in developing countries must include the identification of the primary accident causes. This paper, therefore, seeks to show that the Delphi Technique is a suitable alternative method that can be exploited in generating highway traffic accident data through which the major accident causes can be identified. In order to authenticate the technique used, Korea, a country that underwent similar problems when it was in its early stages of development in addition to the availability of excellent highway safety records in its database, is chosen and utilized for this purpose. Validation of the methodology confirms the technique is suitable for application in developing countries. Furthermore, the Delphi Technique, in combination with the Bayesian Network Model, is utilized in modeling highway traffic accidents and forecasting accident rates in the countries of research. [ABSTRACT FROM AUTHOR]

To investigate pedestrian exposure when only pedestrian-crash data are available, the quasi-induced exposure method is used to identify the factors that contributed to pedestrian-vehicle crashes in Las Vegas from 2004 to 2008. The results show that overall crash severity, light conditions, and weather conditions are potentially risky factors in pedestrian crashes, and the time of day or day of the week are less risky. Multiple-correspondence analysis (MCA) is then used to investigate how pedestrian crash severity is influenced by the interactions among a range of variables. The results indicate that among instances of pedestrian-vehicle crashes cases of property damage only tend to occur during off-peak daytime hours and under dark or dawn light conditions in clear weather. Crashes resulting in injuries usually occur during weekday peak hours in daylight and under rainy conditions. Most fatal crashes occur during off-peak hours, at night on the weekends. [ABSTRACT FROM AUTHOR]

In this paper, we develop a customized path-based algorithm for solving the stochastic multi-class traffic assignment problem with asymmetric interactions, route overlapping, and vehicle restrictions. The algorithm consists of an iterative balancing scheme to find the search direction, a self-regulated averaging line search scheme to determine a suitable stepsize, and a column generation scheme to generate a universal path set for multiple vehicle classes. These three schemes work together in the customized path-based algorithm to solve the stochastic multi-class traffic assignment problem. The solution algorithm simultaneously considers the asymmetric interactions among different vehicle types through the link travel time functions, various vehicle restrictions in a transportation network, and route overlapping using the path-size logit model for accounting random perceptions of network conditions in a stochastic user equilibrium framework. A real network in the city of Winnipeg, Canada, is used to examine the computational performance of the customized path-based algorithm. In addition, sensitivity analyses are conducted to test the algorithmic effectiveness with respect to several model parameters and percentages of trucks in the transportation network. Numerical results reveal that the path-based algorithm with the self-regulated averaging line search scheme is computationally effective in solving the stochastic multi-class traffic assignment problem with different modeling considerations. The algorithm is also computationally robust against various model parameters in the sensitivity analyses. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Distinguishing commuters from non-commuters is important for transportation planning and traffic demand management. A framework to identify commuters using public transit is proposed based on a spatial-temporal clustering algorithm. The framework extracts commute trips by mining spatial-temporal travel patterns depending on whether the travelers' trip chains are complete. The commuting features in terms of travel frequency, time regularity, and spatial regularity are utilized to compare the difference in travel behavior between commuters and non-commuters. The framework is applied to trip data collected from an incentive program implemented by the Metropolitan Transport Commission of Korea. The data records spatial and temporal information on travelers' boarding and alighting points, as well as actual origins and destinations. One trip record constitutes a complete trip chain for travelers who joined the incentive program. The results show that commuters exhibit a higher travel frequency and more regular spatial-temporal travel patterns than non-commuters. It is found that not all commuters travel during morning and evening peaks; some commuters leave work after evening peak. The proposed identification framework based on the spatial-temporal clustering approach is capable of exploiting the inherent spatial-temporal travel patterns of travelers to achieve a reliable identification of commuters. [ABSTRACT FROM AUTHOR]

Estimating long-term vehicle ownership and energy use is essential for national transportation planning, especially for addressing policies regarding climate change. In this paper, long-term vehicle ownership and energy use in Korea is estimated according to income and fuel price scenarios. A modified form of a quasi-logistic growth function is employed to consider the causalities between vehicle ownership and independent variables. Vehicle ownership has been identified to be more sensitive to income change than to fuel price expectations. The likely fuel price increase evaluated in this research would not deter people from buying cars. This implies that future transportation energy conservation policies should be based more on transportation demand management (TDM)–type policies. [ABSTRACT FROM PUBLISHER]

According to the National Highway Traffic Safety Administration (NHTSA), while fatalities from traffic crashes have decreased, the proportion of pedestrian fatalities has steadily increased from 11% to 14% over the past decade. This study aims at identifying two zonal levels factors. The first is to identify hot zones at which pedestrian crashes occurs, while the second are zones where crash-involved pedestrians came from. Bayesian Poisson lognormal simultaneous equation spatial error model (BPLSESEM) was estimated and revealed significant factors for the two target variables. Then, PSIs (potential for safety improvements) were computed using the model. Subsequently, a novel hot zone identification method was suggested to combine both hot zones from where vulnerable pedestrians originated with hot zones where many pedestrian crashes occur. For the former zones, targeted safety education and awareness campaigns can be provided as countermeasures whereas area-wide engineering treatments and enforcement may be effective safety treatments for the latter ones. Thus, it is expected that practitioners are able to suggest appropriate safety treatments for pedestrian crashes using the method and results from this study. [ABSTRACT FROM AUTHOR]

Highlights: [•] Residence characteristics of drivers who caused traffic crashes were investigated. [•] Bayesian Poisson-lognormal model was adopted in this study. [•] Population and commute mode were related with the number of at-fault drivers. [•] Age, commute time, and income were associated with the number of at-fault drivers. [•] Findings from the study can identify residence areas with risky drivers. [Copyright &y& Elsevier]

As a freeway operational management strategy, High-Occupancy Toll (HOT) lanes have been deployed to manage the demand for High-Occupancy Vehicle (HOV) lanes by adjusting the tolls. By doing so, the capacity of freeways with such lanes can be used more efficiently. Periodically, setting the right amount of toll in accordance with the time-varying demand is a key to successful operation of HOT lanes; however, this is often difficult because travellers have heterogeneous willingness to pay for the toll and traffic conditions vary as the demand changes due to the imposition of tolls. This paper proposed an algorithm to determine the optimal level of toll for minimizing the total delay collectively spent by both HOVs and low-occupancy vehicles. Based on real-world traffic and survey data obtained from Gyungbu expressway in South Korea, a case study is presented to verify the applicability of the developed algorithm. The results from the case study show that the proactive dynamic pricing scheme can use the underutilized capacity of HOT lane efficiently and, thereby, shorten total travel time by 22% and generate revenue of more than $8600. Some limitations and future research agendas are also discussed. [ABSTRACT FROM AUTHOR]

Minority status and low-income are two important criteria on which environmental-justice areas are being identified. These unique areal characteristics have been of particular interest to traffic safety analysts in investigating pedestrian safety planning factors in deprived areas. In this study, a pedestrian crash model was developed for these areas explicitly accounting for the spatial autocorrelations of different zonal factors commonly used in the traditional transportation planning models. It was found that the Bayesian Poisson-lognormal model with a spatial effect term performed the best compared to the models without accounting for spatial autocorrelations. [ABSTRACT FROM AUTHOR]

Highlights: [•] Traffic congestion causes by traffic accidents contributes to CO2 emissions. [•] More efficient and prompt responses to accidents lead to reduced CO2 emissions. [•] Presentation of case study assessment of CO2 emissions illustrates linkages. [ABSTRACT FROM AUTHOR]

Abstract: The regulation of overweight trucks is of increasing importance. Quickly growing heavy vehicle volumes over-proportionally contribute to roadway damage. Raising maintenance costs and compromised road safety are also becoming a major concern to managing agencies. Minimizing pavement wear is done by regulating overloaded trucks on major highways at weigh stations. However, due to lengthy inspections and insufficient capacities, weigh stations tend to be inefficient. New practices, using Radio Frequency Identification (RFID) transponders and weigh-in-motion technologies, called preclearance programs, have been set up in a number of countries. The primary aim of this study is to investigate the current issues with regard to the implementation and operation of the preclearance program. The State of Queensland, Australia, is used as a case study. The investigation focuses on three aspects; the first emphasizes on identifying the need for improvement of the current regulation programs in Queensland. Second, the operators of existing preclearance programs are interviewed for their lessons-learned and the marketing strategies used for promoting their programs. The trucking companies in Queensland are interviewed for their experiences with the current weighing practices and attitudes toward the potential preclearance system. Finally, the estimated benefit of the preclearance program deployment in Queensland is analyzed. The penultimate part brings the former four parts together and provides the study findings and recommendations. The framework and study findings could be valuable inputs for other roadway agencies considering a similar preclearance program or looking to promote their existing ones. [Copyright &y& Elsevier]

Abstract: This paper considers the ideal dynamic user optimal (DUO) route choice problem using a route-based variational inequality approach. A discrete time dynamic flow model is developed, which uses link travel time functions to determine time-dependent network states. The proposed flow model is built on discrete time flow variables, to eliminate the discretization process of continuous time based models. Continuity of route travel time functions is proven to establish the existence of a solution, on the condition that the link travel time functions are continuous. Furthermore, flow dispersion and concentration can be simulated, which is expected to enhance the ability of capturing dynamics of traffic movements. A variational inequality formulation based on an alternative cost mapping is proposed, which is derived from a route swapping heuristic approach. As a solution method, the projection-based approach is used since the route travel time functions in our model are not smooth. To increase the performance of the projection-based methods, an efficient implementation of the projection operation is developed. Computational experiences with two example networks are provided to illustrate the model. [Copyright &y& Elsevier]

To convert HOV (high-occupancy vehicle) lanes to HOT (high-occupancy toll) lanes, it is necessary to evaluate the relevant benefits to drivers, to highway maintenance, to traffic management, and to the whole society under various combinations of tolls, motorists’ perception error, and travel demand. This paper assesses the benefit and effect of an HOV/HOT lane project on the I-394 corridor network in the Twin Cities by using an analytical multiclass stochastic dynamic transportation network model with Monte Carlo simulation and the method of successive averages. Specifically, the effects of various toll schemes for HOT lane design and operations are investigated. The results are analyzed, yielding useful insights for the design and evaluation of HOT lanes. [ABSTRACT FROM AUTHOR]

Cycling is gaining popularity both as a mode of travel in urban communities and as an alternative mode to private motorized vehicles due to its wide range of benefits (health, environmental, and economical). However, this change in modal share is not reflected in current transportation planning and travel demand forecasting modeling processes. The existing practices to model bicycle trips in a network are not sophisticated enough to describe the full cyclist experience in route decision-making. This is evident in the existing practices' methodology: the all-or-nothing assignment uses single attributes such as distance, safety, or a composite measure of safety multiplied by distance. The purpose of this article is to develop a multi-class and multi-criteria bicycle traffic assignment model that not only accounts for multiple user classes by acknowledging that there are different types of cyclists with varying levels of biking experience, but also for relevant factors that may affect each user classes behavior in route choice decisions. The multi-class, multi-criteria bicycle traffic assignment model is developed in a two-stage process. The first stage examines key criteria to generate the set of non-dominated (or efficient) routes for each user class, and the second stage determines the flow allocation to efficient routes by user class. Numerical experiments are then conducted to demonstrate the two-stage approach for the multi-class, multi-criteria bicycle traffic assignment model. [ABSTRACT FROM AUTHOR]

Mobility as a Service (MaaS) is an innovative concept, enabled by the ubiquitous availability of digital technologies. Many cities around the world envision MaaS as a way to improve sustainable transportation by reducing the use of fossil fuel-based transportation modes. However, MaaS may also trigger users of environmentally-friendly transportation modes to switch to less sustainable modes, such as taxi and ridesharing. The aim of this study is to explore how different bundling and pricing schemes of MaaS contribute to improving sustainable transportation. In order to analyze individuals' intended choice of MaaS, a stated portfolio choice experiment was developed. A mixed logit model is estimated to investigate the bundle of transportation modes individuals configure when subscribing to MaaS. We explore empirical issues such as which transportation modes they prefer to include in the bundle, and how pricing schemes affect the composition of the bundle. Furthermore, scenario analyses are conducted to assess the impact of pricing schemes on sustainable transportation. Results show that MaaS contributes to improving sustainable transportation in a non-linear manner as a function of decreasing monthly subscription fees and/or increasing length of the subscription. [ABSTRACT FROM AUTHOR]

The article develops a new method that compares activity‐travel patterns in both terms of the sequential order of activities and the shape of activity‐travel trajectory in time and space. The similarity of the list of activities and their order between activity‐travel patterns are computed by a sequence alignment method. The shape of activity‐travel trajectory is compared between the patterns using a path similarity technique that captures the direction and speed of a movement from the current location and the duration of staying at each location. The comparison results, therefore capture how people move around in three‐dimensional space–time choreography that indicates how people conduct which activities in what order. A total of 1,000 individuals are sampled from the data of 2016 Household Travel Survey, South Korea. The data provide the information of individual activity‐travel behavior and personal characteristics. The suggested method computes the pairwise distance matrix, and Ward clustering algorithm segments the pattern groups of similar activity sequences and space–time trajectories. A CHAID analysis then associates personal and household characteristics with the pattern groups to identify important factors for the segmentation. The analysis provides a significant implication in both terms of research and practice in transportation. [ABSTRACT FROM AUTHOR]

This study develops a predictive continuum dynamic user-optimal model for the simultaneous departure time and route choice problem through a variational inequality (VI) approach. A polycentric urban city with multiple central business districts (CBDs) is considered, and travelers are classified into different classes according to their destinations (i.e., CBDs). The road network within the modeling city is assumed to be sufficiently dense and can be viewed as a continuum. A predictive dynamic user-optimal (PDUO) model has been previously used to model traffic flow with a given traffic demand distribution, in which travelers choose the routes that minimize the actual travel cost to the CBD. In this work, we combine the departure time choice with the PDUO model to study the simultaneous departure time and route choice problem. The user-optimal departure time principle is satisfied, which states that for each origin–destination pair, the total costs incurred by travelers departing at any time are equal and minimized. We then present an equivalent VI and solve it using the projection method after discretization based on unstructured meshes. A numerical experiment for an urban city with two CBDs is presented to demonstrate the effectiveness of the numerical algorithm. [ABSTRACT FROM AUTHOR]

This study proposes an integrated simulation approach, which consists of a microscopic traffic simulation model, a vehicle dynamics model, and an emission estimation model, in order to estimate emissions based on more reliable vehicle performance measures. The vehicle performance measures such as engine power and engine speed significantly relate to the amount of emissions, and road curvatures and inclinations are the core inputs affecting these vehicle performance measures. Therefore, providing reliable vehicle performance measures reflecting the road geometric attributes is critical for a reliable emission estimation. This study proposes to use the microscopic traffic simulation model for generating vehicle trajectories, which is advantageous in modeling various traffic situations, and the vehicle dynamics model for producing the vehicle performance measures based on the vehicle trajectories. Finally, the outputs from the vehicle dynamics model are fed into the emission estimation model to compute emission measures. This study conducted a case-study using two road sections, one is a hypothesized road section, including various curvatures and inclinations with regular variations, and the other is a Kesselberg road section, which is an actual geometry in Bayern, Germany. The emission measures are estimated in these case-study road sections using both an existing simulation approach and the proposed integrated simulation approach. The difference between these two emission estimation approaches is discussed in terms of the emission measures, including fuel consumption, nitrogen oxides, and particulate matters. [ABSTRACT FROM PUBLISHER]

Public transportation has been regarded as one of the most sustainable forms of transport, because of which local governments have put efforts in increasing the mode share of public transportation. Recently, not only level of service but also user satisfaction has been focused on for the assessment of transport policy; however, several points have been overlooked in previous research, such as attribute-based satisfaction, the relationship between level of service and satisfaction, and user expectation. This paper deals with these issues while assuming the heterogeneity of satisfaction, which is an indicator of perception. Out-of-vehicle times, particularly headway and access time, were selected in the analysis because they can affect travel behavior of current and potential public transportation customers. In this analysis, pattern-recognition models were applied, and public transportation users were segmented in terms of perception. The results suggest several notable recommendations for public transport policies and investigations. [ABSTRACT FROM AUTHOR]

This paper presents the development of a macroscopic dynamic traffic assignment model for continuum transportation systems with elastic demand. A reactive dynamic user equilibrium model is extended to simulate network equilibrium problems for an urban area with multiple central business districts (CBDs). Each copy of traffic flow reactively makes route choice decisions to minimize the total travel cost from origin to destination, based on instantaneous traffic information from a radio broadcasting service or route guidance system. The elastic demand function for each copy of flow is associated with its total instantaneous travel cost. The model is solved by a cell-centered finite volume method for conservation law equations and a fast sweeping method for Eikonal-type equations on unstructured grids. Numerical experiments for an urban traffic network with two CBDs are presented to verify the rationality of the model and the validity of the numerical method. The numerical results indicate that the model captures some macroscopic characteristics of two copies of flow interacting in time-varying urban transportation systems, e.g., the spatial distributions of the flow density and flux and the path choice behavior in response to elastic demand, and can describe traffic equilibrium phenomena, such as self-organization and traffic congestion build-up and dissipation. [ABSTRACT FROM AUTHOR]

The paper proposes a scheme by combining the Runge–Kutta discontinuous Galerkin method with a δ -mapping algorithm for solving hyperbolic conservation laws with discontinuous fluxes. This hybrid scheme is particularly applied to nonlinear elasticity in heterogeneous media and multi-class traffic flow with inhomogeneous road conditions. Numerical examples indicate the scheme’s efficiency in resolving complex waves of the two systems. Moreover, the discussion implies that the so-called δ -mapping algorithm can also be combined with any other classical methods for solving similar problems in general. [ABSTRACT FROM AUTHOR]

This article proposes a novel urban system equilibrium model for design of a tradable location tax credit scheme to balance traffic congestion and environmental externalities. In the proposed model, the interaction between the location tax credit scheme and households' residential location choices is explicitly considered. It is assumed that the authority initially allocates the credits to all households in a uniform way, and the households pay a certain amount of credits for housing consumptions, relying on the traffic congestion and environmental externalities that they cause. The credits are traded among households through a free market, and the tax revenue due to credit trading is considered as a part of household's income to be redistributed through household's income budget constraint. For a given credit scheme, households' residential location choices and housing market structure in terms of housing prices and space can be endogenously determined by the urban system equilibrium and the price per unit of credit is governed by the credit market equilibrium. A social welfare maximization model is presented to determine the total amount of credits issued. The results show that implementation of the tradable location tax credit scheme can rationalize the urban residential density and promote the efficiency of the urban system in terms of social welfare. [ABSTRACT FROM AUTHOR]

Car-following models, which describe the reactions of the driver of a following car to the changes of the leading car, are essential for the development of traffic flow theory. A car-following model with a stochastic memory effect is considered to be more realistic in modeling drivers’ behavior. Because a gamma-distributed memory function has been shown to outperform other forms according to empirical data, in this study, we thus focus on a car-following model with a gamma-distributed memory effect; analytical and numerical studies are then conducted for stability analysis. Accordingly, the general expression of undamped and stability points is achieved by analytical study. The numerical results show great agreement with the analytical results: introducing the effect of the driver’s memory causes the stable regions to weaken slightly, but the metastable region is obviously enlarged. In addition, a numerical study is performed to further analyze the variation of the stable and unstable regions with respect to the different profiles of gamma distribution. [ABSTRACT FROM AUTHOR]

With increasing concerns about environmental and energy issues in many large Chinese cities, local authorities are introducing public bicycle schemes to promote the use of green transportation modes. This paper proposes a novel model for investigating the effects of the public bicycle schemes in a congested multi-modal road network with auto, bus, and public bicycle travel. The decision-making process of travelers regarding travel modes and route choices is assumed to follow a hierarchical choice structure. The effects of pollution emissions by motorized vehicles (i.e., autos and buses), crowding discomfort in buses, and riding fatigue on bicycles are considered in the proposed model. The multi-modal travel choice equilibrium problem is formulated as an equivalent variational inequality problem. The existence and uniqueness of the solution of the proposed model are examined. A heuristic solution algorithm that combines a diagonalization approach and the method of successive averages is adapted to solve the proposed model. A numerical example is given to illustrate the application of the proposed model and solution algorithm. Findings are reported on the effects of the public bicycle schemes and emission tax policy on the multi-modal transportation system. The optimal public bicycle rental price and emission tax for maximization of social welfare can also be determined by the proposed model. [ABSTRACT FROM PUBLISHER]

This paper addresses the road toll pricing and capacity investment problem in a congested road network in a multicriteria decision-making framework. A goal programming approach is used in which the following four major goals are considered: (1) cost recovery, (2) service level, (3) environmental, and (4) equity. The multiobjective road toll pricing and capacity investment problem is formulated as a bilevel goal programming model. The upper level of the model aims to minimize the deviations from stated goals for a given priority ranking of the goals, while the lower level is the road users' route choice equilibrium problem. A simulated annealing-based solution algorithm is developed to solve the proposed model. Numerical results show that the priority structure of the goals can significantly affect the road toll pricing and capacity investment decisions. The simulated annealing-based solution algorithm outperforms the sensitivity analysis-based solution algorithm in terms of solution quality. The proposed methodology provides an avenue for understanding the trade-offs among conflicting objectives and for designing a financially and environmentally sustainable transportation system. [ABSTRACT FROM AUTHOR]

The discontinuous Galerkin (DG) scheme is used to solve a conserved higher-order (CHO) traffic flow model by exploring several Riemann solvers. The second-order accurate DG scheme is found to be adequate in that the accuracy is comparable to the weighted essentially non-oscillatory (WENO) scheme with fifth-order accuracy and much better than the scheme with first-order accuracy in resolving a wide moving jam with a shock profile. Moreover, it considerably reduces the differences between the proposed solvers in generating numerical viscosities or errors. Thus, this scheme can maintain high efficiency when a simple solver is adopted. The scheme could be extended to solve more complex problems, such as those related to traffic flow in a network. [ABSTRACT FROM AUTHOR]

Abstract: Steady-state traffic flow on a ring road with up- and down-slopes is investigated using a semi-discrete model. By exploiting the relations between the semi-discrete and continuum models, a steady-state solution is uniquely determined for a given total number of vehicles on a ring road. The solution is exact and always stable with respect to the first-order continuum model, whereas it is a good approximation with respect to the semi-discrete model provided that the involved equilibrium constant states are linearly stable. In other cases, the instability of one or more equilibria could trigger stop-and-go waves propagating in certain sections of road or throughout the ring road. The indicated results are reasonable and thus physically significant for better understanding of real-world traffic flow on inhomogeneous roads, such as those with junctions or bottlenecks. [Copyright &y& Elsevier]

Highlights: [•] We consider two effects, perceived potential field and aggregated force vector field, in a crowd. [•] The perceived cost potential is used to navigate pedestrians moving in local low-density domains. [•] The aggregated force vector field is applied to describe the pushing force among pedestrians. [Copyright &y& Elsevier]

The paper evaluates the effectiveness of various traffic calming measures from the perspectives of traffic performance and safety, and environmental and public health impacts. The proposed framework was applied to four calming measures – two types of speed humps, speed tables, and chicanes – to demonstrate its usefulness and applicability. A field experiment using probe vehicles equipped with global positioning system devices was conducted to obtain vehicle trajectory data for use in more realistic simulations. In addition, a recently developed vehicle emissions model was used for more accurate evaluation of environmental and public health impacts. The results show that chicane is better than the other types of traffic calming measures considered, except in terms of vehicle emissions. [ABSTRACT FROM AUTHOR]

Highlights: [•] We show that the original PDUO-C model is not well posed due to an inconsistency in the path-choice strategy under certain conditions. [•] We revisit the PDUO-C problem, and construct an improved model that rectifies the inconsistency in the original model. [•] We propose a self-adaptive MSA that can automatically determine the optimal MSA step size using the least squares method without prior information. [ABSTRACT FROM AUTHOR]

Abstract: A wide array of spatial units has been explored in macro-level modeling. With the advancement of Geographic Information System (GIS) analysts are able to analyze crashes for various geographical units. However, a clear guideline on which geographic entity should be chosen is not present. Macro level safety analysis is at the core of transportation safety planning (TSP) which in turn is a key in many aspects of policy and decision making of safety investments. The preference of spatial unit can vary with the dependent variable of the model. Or, for a specific dependent variable, models may be invariant to multiple spatial units by producing a similar goodness-of-fits. In this study three different crash models were investigated for traffic analysis zones (TAZs), block groups (BGs) and census tracts (CTs) of two counties in Florida. The models were developed for the total crashes, severe crashes and pedestrian crashes in this region. The primary objective of the study was to explore and investigate the effect of zonal variation (scale and zoning) on these specific types of crash models. These models were developed based on various roadway characteristics and census variables (e.g., land use, socio-economic, etc.). It was found that the significance of explanatory variables is not consistent among models based on different zoning systems. Although the difference in variable significance across geographic units was found, the results also show that the sign of the coefficients are reasonable and explainable in all models. Key findings of this study are, first, signs of coefficients are consistent if these variables are significant in models with same response variables, even if geographic units are different. Second, the number of significant variables is affected by response variables and also geographic units. Admittedly, TAZs are now the only traffic related zone system, thus TAZs are being widely used by transportation planners and frequently utilized in research related to macroscopic crash analysis. Nevertheless, considering that TAZs are not delineated for traffic crash analysis but they were designed for the long range transportation plans, TAZs might not be the optimal zone system for traffic crash modeling at the macroscopic level. Therefore, it recommended that other zone systems be explored for crash analysis as well. [Copyright &y& Elsevier]

Abstract: This paper proposes a new model for investigating the effects of integrated rail and property development on the design of rail line services in a linear monocentric city, in which the property development rights at railway station areas are conferred to a private rail operator. The proposed model allows an explicit consideration of the interaction between two types of agents in the economy: (1) a private rail operator who seeks to optimize rail service variables—rail line length, number and spacing of stations, headway and fare—to maximize its own net profit, which is the sum of revenues from passenger fare-box and property development; and (2) households who choose the residential locations that maximize their own utilities subject to a budget constraint. The solution properties of the proposed model are analyzed, and a heuristic solution algorithm is presented. An illustrative example is used to show the application of the proposed model. The findings show that integrated rail and property development can change a city’s land-use pattern and housing market (in terms of housing density, space, and price), and its economic viability is closely related to household income level and residential density of the city. [Copyright &y& Elsevier]

Abstract: An algorithm for an extended reactive dynamic user equilibrium model of pedestrian counterflow as a continuum is developed. It is based on a cell-centered high-resolution finite volume scheme with a fast sweeping method for an Eikonal-type equation on an orthogonal grid. A high-order total variation diminishing Runge–Kutta method is adopted for the time integration of semi-discrete equations. The numerical results demonstrate the rationality of the model and efficiency of the algorithm. Some crowd pedestrian flow phenomena, such as dynamic lane formation in bi-directional flow, are observed which are helpful for a global comprehension of pedestrian dynamics. Also, the model can be utilized with different potential applications. [Copyright &y& Elsevier]

Abstract: Research on weather effects has focused on snow- or rain-related crashes. However, there is a lack of understanding of crashes that occur during fog or smoke (FS). This study presents a comprehensive examination of FS-related crashes using crash data from Florida between 2003 and 2007. A two-stage research strategy was implemented (1) to examine FS-related crash characteristics with respect to temporal distribution, influential factors and crash types and (2) to estimate the effects of various factors on injury severity given that a FS-related crash has occurred. The morning hours from December to February are the prevalent times for FS-related crashes. Compared to crashes under clear-visibility conditions, FS-related crashes tend to result in more severe injuries and involve more vehicles. Head-on and rear-end crashes are the two most common crash types in terms of crash risk and severity. These crashes were more prevalent on high-speed roads, undivided roads, roads with no sidewalks and two-lane rural roads. Moreover, FS-related crashes were more likely to occur at night without street lighting, leading to more severe injuries. [Copyright &y& Elsevier]