We developed a path-based partial linearization algorithm for solving the combined modal split and traffic assignment (CMSTA) problem with captive mode users and overlapping routes. The dogit model was adopted to model captive mode users, while the path-size logit (PSL) model was used to handle the route-overlapping problem. A convex mathematical programming formulation was used in this special CMSTA problem, which combines the dogit mode choice and the PSL route choice to form a combined dogit-PSL model. To improve the efficiency of the path-based partial linearization algorithm, a self-regulated averaging line search strategy was incorporated to minimize computational efforts while ensuring convergence. Using a real city network in Seoul, Korea, numerical results were used to examine the efficiency of the proposed algorithm and the effectiveness of how the combined dogit-PSL model handled captive mode users and route overlapping in a multimodal transportation network.
This paper proposes an approach to estimate the value of motorcycle equivalent units (MEU), which are very important for studies of motorcycle-dominated traffic flows. With some minor adjustments, the proposed approach can also be applied to car-dominated traffic flows. A model for MEU estimation was developed using real-world traffic data collected in Vietnam. The proposed model describes the relationship between MEU values and significant parameters such as trajectory, velocity, and safety distance. The MEU values estimated using the proposed model were compared with values estimated using previously proposed models. The results show that the MEU values estimated using the proposed model are quite stable and can be applied to many types of roadway geometries in developing countries.
To reduce the impact of drunk-driving behavior on accident risks, this study made an initial attempt to evaluate the public acceptance of designated driver services (DDS) in the Vietnamese context. A stated preference (SP) survey was implemented to capture more than 300 car and motorcycle drivers' preferences for various hypothetical DDS in Hanoi. The collected SP data were analyzed by employing a panel mixed logit model with both social interactions and heterogenous tastes. Positive social interactions leading the choice behavior to an equilibrium were found. This new service seems more effective to meet the needs of middle-aged people and office workers, who have the highest risk of drunk driving among all population groups. The modeling results further suggest that to reduce the prevalence of drunk-driving behavior and encourage people to use the new DDS, the government needs to tighten law enforcement, raise drunk-driving penalties, maintain the low cost of DDS, and educate people to internally mitigate their negative attitudes about drunk-driving behavior.
This paper focuses on two typical behaviors, namely “cut tail” and “giving way” of a motorcycle at an intersection. First, the study applied the anticipation movement approach and two-player game theory to describe the motorcycle's behaviors. The anticipation movement approach is applied to depict the manner of detecting and reacting to the conflict areas. Twoplayer game theory is employed to describe the situation that the motorcycle perceives the information and makes the decision. Second, the intersection's simulation has been developed based on the suggested model for mixed-traffic condition by using an integrated agent-based modeling environment. Because of the effective mechanism for a motorcycle to tackle the conflicts, the behaviors are truly reproduced in the simulation. The result demonstrated that the suggested model and the agent-based environment are sufficient to replicate the motorcycles' behaviors.
The paratransit system is the only mode of public transport available in Kandahar city and operates as an informal transport sector. Using revealed and stated preference techniques, this study aimed to elaborate on the characteristics and usage patterns of the current system and identify the potential for introducing a regular bus system. The results demonstrated that the overall ridership of the sector is very low for daily trips because of the irregularity and limited coverage of the paratransit system and the dominance of private vehicles. The multinomial logit model results suggest that Kandahar city residents are more sensitive to the travel time for a public transport mode compared to its travel cost. In other words, speed, waiting time, number of stops/stations, and the distance between the stops play a vital role in terms of ridership. Additionally, age and income are also important factors in planning a bus system.
Vehicle discharge is a major factor that influences the design of traffic signals. Emerging countries with nonlane-based mixed traffic operations have distinctly different vehicle discharge characteristics compared with countries with disciplined traffic operations. In the case of nonlane-based traffic, vehicles occupy any available space near an intersection and do not necessarily form a lane-based queue. As a result, prevailing trends of vehicle discharge characteristics, such as discharge headway and queue discharge rate, are not directly applicable. In this study, a new measure, the vehicle passing interval, was adopted to investigate the dynamics of vehicle discharge in such traffic conditions. A case study was conducted using several two-lane signalized approaches in Kolkata, India. The vehicle passing interval was found to be effective in capturing heterogeneity with respect to vehicle category, the lateral and longitudinal position of vehicles, and variation in discharge rate over different intervals of green time.
To construct a traffic network that is resilient to natural and man-made disasters, it is necessary to assess the reliability of the network. This article proposes a stochastic user equilibrium assignment model under stochastic origin-destination (OD) demand and link capacity following lognormal distributions. The nonnegative property of the lognormal distribution makes it possible to assume any degraded state of links, including disruption or reduction of lane(s), by varying the stochastic link capacities. This model assigns the OD demand to a road network based on the stochastic user equilibrium principle. Thus, the model can compare the link (or path) flows and link (or path) travel costs in the normal state with those in the degraded state, and is formulated as a logit-based fixed-point problem. We conducted numerical experiments to compare the assigned flow and travel cost in the normal state with those in the degraded state.
Several real-time crash prediction (RTCP) models have been proposed using Bayesian networks (BNs), which are probabilistic graphical modeling methods offering a great degree of robustness. These models offer real-time applicability, high prediction success, a capacity to handle missing data, and the possibility of a flexible variable space. However, to develop an advanced RTCP model using BN, it is imperative to identify the most influential traffic variables and their combinations. This study proposes BN-based RTCP models with 24 combinations of 12 traffic variables. After modeling, their performances were validated and compared to identify the preferable combinations of input variables. The models constructed with differences between the upstream and downstream congestion index, flow, speed, and the upstream congestion index as variables proved to be the most effective combination of input variables.
The capacitated arc routing problem (CARP) is a difficult combinatorial optimization problem that has wide applicability in real-world logistics problems. The CARP involves finding a set of routes with minimum costs for a set of demand arcs with vehicle capacity limitations. Due to its NP-hard property, the CARP cannot be solved within reasonable time by exact algorithms. In recent years, metaheuristic algorithms have been developed to solve the CARP. Here, we propose an ant colony optimization algorithm with path relinking (ACOPR) to solve the problem. The proposed ACOPR was tested with seven benchmark sets of 181 instances from the literature for its effectiveness and compared with the existing best-performing metaheuristics. The computational results show that ACOPR is competitive with the compared state-of-the-art metaheuristic algorithms.
This paper offers empirical evidence regarding the impacts of rural road improvement on the poor in Cambodia, based on results of structured interview surveys, conducted one year after the completion of civil works, and its follow-up survey. Those surveys were done in three rural areas along the rehabilitated roads, and the collected data were examined on (1) ownership of wheeled and/or motorized-modal options; (2) travel frequencies for income generations; and (3) household's economic status, to know how the road improvement impacted local population's livelihoods and how such impacts differed among the areas of different poverty rates. The examination indicated that changes related to those three were not necessarily observed for most individuals in the wealthiest region. Rather, the following could be more influential for impacts to be generated on individuals: connectivity to major economic centers, opportunities and abilities to reach new job opportunities, and local economic structures.
When entering an emerging market, an international company may initially focus on establishing production plants and its upstream parts/raw materials supply system, and rely on local sales agents for outbound physical distribution. However, once familiar with the business environment, the international company may consider building up its own distribution system to improve its profit margin and customer service. In this context, for a distribution system of four layers, this study examines the location problem of the distribution center, given the fixed locations of the suppliers, plants, and retailers. In particular, we consider the integration of the supplier-plant and plant-distribution center transportation in this strategic location decision problem. We develop a mixed-integer programming model and design a heuristic solution algorithm based on Lagrangian relaxation. In a numerical experiment, the solution quality is found to be close to optimality, and the computation time is acceptable in terms of strategic decision-making.
A large body of evidence supports that driving stress both directly and indirectly leads to traffic accidents. Therefore, driving stress is an important issue to reduce traffic accidents. The aim of this study was to evaluate the impact of roadway conditions and land-use on driving stress among professional drivers and to give some suggestions to reduce the driving stress. Multiple indicators multiple causes (MIMIC) model was used to empirically investigate which variables of the roadway condition and land-use affected the driving stress among drivers in Yangon, Myanmar. Standard deviation of normal to normal RR intervals (SDNN), Square root of the mean squared differences between successive RR intervals (RMSSD), Percentage value of consecutive RR intervals that differ more than 50 ms (pNN50), Baseline width of the RR interval histogram (TINN), Balance between the sympathetic nervous system activity and the parasympathetic nervous system activity (fast Fourier transform) (LF/HF (FFT)) and Balance between the sympathetic nervous system activity and the parasympathetic nervous system activity (Autoregressive) (LF/HF (AR)) are used as driving stress indicator. The results suggest that certain roadway conditions reduce driving stress. Specifically, using roundabouts and traffic lights at intersections to control traffic and increasing the number of lanes are the effective ways to reduce driving stress. However, roundabouts rather than traffic lights are more efficient. Conversely, industrial zones are associated with an increase in driving stress.
This study empirically explores the association of bike-sharing systems (BSSs) with destination satisfaction in overseas tourists. The selection of attributes of destination satisfaction and BSS for analysis was based on literature reviews and tourist interviews. Then, a questionnaire survey was conducted on overseas tourists in Taipei, Taiwan. The sample included 400 effective responses, which were analyzed using ordered logit regressions. The empirical data showed that overseas tourist perceptions of multiple BSS attributes are associated with tourist destination satisfaction. Specifically, quality of shared bikes and enjoyment, accessibility, and safety of BSS use were the significant attributes explaining destination satisfaction. The empirical results broaden the understanding of the role of public transport in tourist satisfaction and produce new policy directions for promoting city bike tourism.