Transportation Letters

Shafabakhsh, Gholam Ali; Famili, Afshin; Akbari, Mahdi

doi: 10.1080/19427867.2016.1138605pmid: N/A

In this paper, to study the frequency and severity of traffic accidents, a combination of geographic information system and spatial analysis has been used. For this purpose, methods of planar and network statistics including kernel density estimation and nearest neighbor distance analysis were applied for three types of accidents including fatal, injury, and material property damages. In addition, drawbacks of the traditional planar point pattern and the benefits of network analysis are offered. The network statistics are executed through SANET version 4 and ArcMap on the Semnan–Garmsar road in Iran. The nearest neighbor output analysis is consist of four curves, and regarding the fact that the amounts for accidents resulting in fatalities, injuries, and damages, the observed value curve is above the 5% confidence interval; accidents in the study region are more clustered than would be expected by random chance.

Sonu, Mathew; Dhamaniya, Ashish; Arkatkar, Shriniwas; Joshi, Gaurang

doi: 10.1080/19427867.2016.1154685pmid: N/A

This study is carried out to estimate the passenger car unit (PCU) values of different vehicle categories at a typical four-legged roundabout based on the concept of time occupancy. A stream equivalency factor (k) has also been developed based on the estimated PCU to convert the heterogeneous traffic flow into a homogenous stream equivalent without making use of PCU factors. Relationship between entry flow and circulatory flow has been plotted based on the observed data corresponding to the time period in which there was queue formation in the approach. Further, estimated critical gap and follow-up time have been used to derive the capacity by HCM 2010 equation. A multiplicative adjustment factor is suggested for the use of HCM 2010 equation directly in the field to estimate entry flow under heterogeneous traffic condition. The study results may be suitable for revising the code of practice, named IRC 65–1976, and useful for ongoing national-level efforts of developing Indian Highway Capacity Manual.

Chakraborty, Shantanu; Srinivasan, Karthik K.

doi: 10.1080/19427867.2016.1193309pmid: N/A

Abstract Two-fluid model quantifies traffic performance on a network by studying the interaction between moving and stopped vehicles in the traffic stream. The broad objective of this study is to investigate the presence and possible impact of measurement and modeling errors (non-ergodicity and endogeneity) on two-fluid model estimates under mixed traffic conditions. This objective is pursued based on travel time and running time data obtained from six-lane roads in Chennai city. To address non-ergodicity, a suitable temporal disaggregation scheme is proposed. An orthogonal regression model is applied that accounts for measurement errors in running times and trip times. To handle endogeneity, omitted variable bias correction is applied by adding two variables. The proposed non-ergodic model, correcting for both measurement error and endogeneity, provides a better fit and more accurate estimates than conventional model. These measurement and modeling errors also affect critical traffic flow parameters and level of service benchmarks.

Mondal, Satyajit; Chakraborty, Sandip; Roy, Sudip Kumar; Gupta, Ankit

doi: 10.1080/19427867.2017.1293313pmid: N/A

Abstract Rapid urbanization increases the number of vehicles on a road section significantly throughout the country. Traffic in India is generally heterogeneous consisting of variety of vehicles which comprise wide range of static and dynamic characteristics. To estimate volume of such heterogeneous traffic it is essential to convert the different types of vehicles into equivalent passenger cars and express the volume in terms of Passenger Car Unit (PCU) per hour. The equivalency unit is universally adopted for measurement of traffic volume and the value is obtained by taking the passenger car as the ‘Standard Vehicle.’ The present study has been concentrated on four and six lane divided urban arterials in Kolkata. The PCU of vehicles have been presented for both categories of urban roads and the values are found to be higher than the values given in IRC: 106-1990. It has also been observed that, PCU values of different types of vehicles have been found to be different for different ranges of volume, composition and v/c ratio. Mathematical relationships have been developed on the basis of the variation of PCU with traffic stream parameters. The relationships are developed to forecast the PCU for several vehicular categories that have been statistically validated for different ranges of traffic stream parameters.

Lin, Hong-Zhi; Zhang, Yongping

doi: 10.1080/19427867.2022.2146868pmid: N/A

This paper aims topropose a method to determine the optimal deployment of cordon sanitaire for epidemic control. A bi-level multi-objective programming model is proposed where the lower level is transportation system equilibrium with queueing time to predict link traffic flow, and the upper level is queueing network design, which is a multi-objective integer nonlinear programming model. The primary objective is to minimize the total operation cost of servers with a predetermined waiting time constraint, and the secondary objective is to reach queueing equity. A heuristic algorithm is designed where the method of successive averages is adopted for the lower-level model, and a genetic algorithm is designed for the upper-level model. The computational results show that the methods can find a good heuristic optimal solution. These methods are useful for planners to determine the optimal deployment of cordon sanitaire for disease control and prevention purposes.

Rui, Rong; Yao, Xusheng; Ye, Shunqiang; Ma, Shoufeng

doi: 10.1080/19427867.2022.2148068pmid: N/A

Focusing on the crossing scenarios of pedestrians and autonomous vehicles (AVs) at unsignalized road sections, this study proposes an evolutionary game model considering the related benefits of AVs, pedestrians and traffic managers, and it explores the impact of policy intervention. The game analysis results indicate that strategies of the three agents are closely associated with pedestrians’ trust in driverless technology, human-vehicle communication and government regulation. In cases where regulation exists, increasing the AV supervision threat would facilitate the equilibrium to evolve toward pedestrians crossing and AVs yielding. In addition, we unexpectedly find that the introduction of crash probability information cannot boost the equilibrium outcomes in the expected direction, which may be related to information overload. Finally, this study verifies the validity of the model through numerical simulations and provides managerial implications with respect to driverless technology promotion, communication device design and regulatory policy formulation.

Song, Maocan; Lu, Bin; Cheng, Lin; Sun, Chao

doi: 10.1080/19427867.2022.2148368pmid: N/A

We study the capacitated arc routing problem in the state-space-time network. A multi-commodity network flow model is formulated in the state-space-time network. Two Lagrangian relaxation-based decomposition methods are developed to tackle this problem. By dualizing the coupling constraints to the objective function, the Lagrangian relaxed problem (LR) can be decomposed into several routing subproblems in the state-space-time network. Then we extend quadratic penalty terms to the LR and obtain an augmented Lagrangian relaxed problem (ALR). By applying the alternating direction method of multipliers and linearization techniques, we decompose the ALR into a sequence of routing subproblems. We solve these subproblems of LR and ALR by a time-dependent dynamic programming algorithm. Feasible solutions are produced according to the result of the LR or ALR. The Lagrangian multipliers are updated by the subgradient optimization method. We implement the proposed methods in three networks, showing that the ALR-based method has better performance.

Li, Xuefeng; Du, Mingyang; Kwan, Mei-Po

doi: 10.1080/19427867.2022.2150705pmid: N/A

In practice, the ride-hailing platform generally provides two products: express services and ridesplitting services, and driver resources are usually shared across these two products on the supply side, i.e., hybrid ride-hailing mode. This study tackles the order dispatch problem with considering flexible one-to-three matching strategy under hybrid modes. In this problem, if a driver serves express requests, only one order can be matched with; if a driver serves ridesplitting requests, this driver can be matched with at most three orders simultaneously or sequentially. Considering one-to-three matching, en-route matching, and multiple passengers per order, this problem is formulated as a multi-objective integer programming, a hierarchical approach is adopted to address it. Using the ride-hailing trip data, we examine characteristics of this problem, such as the impact of service priority and the benefits of one-to-three matching. Finally, some beneficial management implications are proposed to improve the operation of the ride-hailing service.

Wang, Meng; Zhang, Xi-Xi; Liu, Yong

doi: 10.1080/19427867.2022.2152960pmid: N/A

The rapid development of free-floating bike sharing (FFBS) has caused the problem of disorderly parking. Previous studies exploring users’ disorderly parking behavior of the FFBS system often ignore the influential factors from the perspective of social psychology. Based on the theory of adolescent egocentrism, this study builds a research model of perceived invulnerability to explore users’ regulated parking intentions by using past behaviors as moderators. Data from 292 FFBS users and partial least squares structural equation modeling (PLS-SEM) were used to verify the research model and hypotheses. The findings show that perceived invulnerability promotes disorderly parking intention and the positive moderating effect of past behavior. Thus, this study not only provides support for the mechanism of FFBS users’ sense of invulnerability, but also provides effective governance suggestions for managers.

Pan, Hengyan; Wang, Yonggang; Szűcs, Gábor

doi: 10.1080/19427867.2022.2157075pmid: N/A

As a product of China’s transportation development in the last decade, the issue of road traffic crashes among ride-hailing drivers has become a growing concern for public safety. This study aims to investigate the human factors contributing to traffic crashes among traditional taxi and ride-hailing drivers, and to compare the similarities and differences between the two groups of drivers. The data was collected from 877 taxi drivers and 906 full-time ride-hailing drivers through a self-reported survey. The structural equation model was used to investigate structural interrelationships between the financial burden, work-related fatigue (WRF), road safety attitude, aberrant driving behaviors (ADBs) of the drivers and their influences on work-traffic crashes. Relevant results showed that there were significant differences in the work status between the two groups of drivers. The heavy economic burden increased the perception of WRF among taxi drivers and contributed to traffic crashes. Ride-hailing drivers had a more positive attitude toward road safety and controlled their ADBs better. These results will help formulate policy recommendations aimed at improving road safety among taxi and ride-hailing drivers.