Forecasting ridership for a metropolitan transit authority

The recent volatility in gasoline prices and the economic downturn have made the management of public transportation systems particularly challenging. Accurate forecasts of ridership are necessary for the planning and operation of transit services. In this paper, monthly ridership of the Metropolitan Tulsa Transit Authority is analyzed to identify the relevant factors that influence transit use. Alternative forecasting models are also developed and evaluated based on these factors—using regression analysis (with autoregressive error correction), neural networks, and ARIMA models—to predict transit ridership. It is found that a simple combination of these forecasting methodologies yields greater forecast accuracy than the individual models separately. Finally, a scenario analysis is conducted to assess the impact of transit policies on long-term ridership.     

Constrained nested logit model: formulation and estimation

A model of traveller behaviour should recognise the exogenous and endogenous factors that limit the choice set of users. These factors impose constraints on the decision maker, which constraints may be considered implicitly, as soft constraints imposing thresholds on the perception of changes in attribute values, or explicitly as hard constraints. The purpose of this paper is twofold: (1) To present a constrained nested logit-type choice model to cope with hard constraints. This model is derived from the entropy-maximizing framework. (2) To describe a general framework to deal with (dynamic) non-linear utilities. This approach is based on Reproducing Kernel Hilbert Spaces. The resulting model allows the dynamic aspect and the constraints on the choice process to be represented simultaneously. A novel estimation procedure is introduced in which the utilities are viewed as the parameters of the proposed model instead of attribute weights as in the classical linear models. A discussion on over-specification of the proposed model is presented. This model is applied to a synthetic test problem and to a railway service choice problem in which users choose a service depending on the timetable, ticket price, travel time and seat availability (which imposes capacity constraints). Results show (1) the relevance of incorporating constraints into the choice models, (2) that the constrained models appear to be a better fit than the counterpart unconstrained choice models; and (3) the viability of the approach, in a real case study of railway services on the Madrid–Seville corridor (Spain).     

Epilogue: the new frontiers of behavioral research on the interrelationships between ICT,activities, time use and mobility

This special issue is a product of the international symposium on “ICT, Activities, Time Use and Travel” that was hosted by Nanjing University from 16 to 18 July 2016. The symposium brought together leading scholars from all over the world to congregate with Chinese scholars and students and to share and discuss the research frontiers at this nexus. It was motivated by a recognition of the changing goals and scope of Information and Communications Technology (ICT) research in conjunction with the development of new ICTs and the emergence of new ICT-enabled behaviors. Consequently, the symposium and later this special issue have drawn together significant scholarly contributions that provide new behavioral insights as well as new theoretical and methodological advances. The symposium culminated in three roundtable panel discussions addressing the following cross-cutting themes: (1) time use while travelling (led by Glenn Lyons); (2) ICT and travel behavior (led by Pat Mokhtarian); and (3) Big Data, activities and urban space (led by Eran Ben-Elia). In this epilogue to the special issue we offer a distillation of these discussions.     

The taxi industry: working conditions and health of drivers,a literature review

The taxi industry plays an important role in urban transportation systems, both in economic and mobility terms. In the case of the former, it provides employment for a large number of people and circulates significant amounts of money. In the case of the latter, it is a flexible means of transportation capable of arriving at any destination. Although the way the taxi industry is organised varies across countries and even within countries, some factors are shared at varying latitudes of the globe. Working conditions, habits, health, and exposure to road crashes have been a subject of interest for researchers from various disciplines, including medicine, psychology, and economics. However, much of this research focuses on a part of the problem and is not mutually referential. A review of the literature may be useful not only to researchers of diverse disciplines but also to industry representatives and those public officials responsible for transportation, road safety and health policy. This article provides a comprehensive review of the working conditions of taxi drivers, their relationship to road risk exposure and their consequences on the health of workers. It also includes information on coping strategies and protective behaviors. The review is based on a Scopus database search. The search covered the period from 1990 to 2015. This initial search was complemented with other database searches, which yielded some additional studies. Our goal was to summarise existing knowledge, identify possible lines of research and suggest some practical recommendations. It would be important (a) to reduce the workload, establish adequate time for breaks, and provide access to healthcare, (b) to implement actions to promote and maintain healthy habits, (c) to diagnose, detect and treat indicators of occupational fatigue and stress, and (d) to develop programs that make it possible to evaluate work concerns and broaden coping strategies to foster positive changes.     

考虑跨肩管土作用的悬跨管道涡激振动特性研究

海底悬跨管道涡激振动是一个复杂的流场-管道结构-跨肩土体耦合问题,其发生机理和振动特性十分复杂,特别是两端跨肩处管土作用对涡激振动的影响有待深入讨论。为此,文章引入了P-y曲线描绘跨肩处管土耦合作用,提出了基于管道位移和速度的新非线性土体弹簧模型,根据能量平衡原理计算土体阻尼,采用尾流振子模型模拟悬跨管段流固耦合作用,建立了考虑流—固—土多场耦合作用的海底悬跨管道涡激振动预报模型,并重点研究了考虑跨肩管土作用时,悬跨管道涡激振动的诸多特性。     

Experimental and Numerical Study on the Behaviors of Deep-Buried Water-Storage and Drainage Shield Tunnels北大核心CSCD

Deep-buried water-storage and drainage shield tunnels, which are different from road and subway shield tunnels in terms of computation theory, construction technology and operation maintenance, would bear high inner water pressure and large earth pressure. In view of the change of the bearing mode for the lining structure of water-storage and drainage shield tunnels, a full-ring test and numerical analysis are carried out to study the influence of inner water pressure, staggered joint assembly and bolt installation types on the behaviors of water-storage and drainage shield tunnels. The results show that the deformation of the straight-jointed water-storage and drainage shield tunnel varies greatly from the state of empty water to that of full water; and the vertical and horizontal convergence deformations of the tunnel with inner water pressure of 0.6 MPa are 2.2 times and 3.2 times of that without inner water pressure, respectively. The convergence deformation, and the maximum joint opening and bolt tension of stagger-jointed lining structure decrease by 15%-25% and 25%- 40%, respectively, compared with that of the straight-jointed water-storage and drainage shield tunnel. The bolts at the segmental joints will yield because of the increase of inner water pressure and the first occurrence of bolt yield phenomenon is located near the position on the lining structure which is under the action of maximum negative bending moment; because the failure of shield tunnel is always caused by the yield of joint bolts, this position is the weak point for the deep-buried water-storage and drainage shield tunnel. For the water-storage and drainage shield tunnel based on the connection with double rows of bolts, the bolts near the outer arc surface of segmental joints in the area of 90 degree in the vault and arch bottom can be removed; the bolts near the inner arc surface of the segmental joints within the 90 degree of the haunch must be installed, otherwise, the tensile force of the bolts at the segmental joint near the maximum negative bending moment will increase by 5%-14%. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Study on the Stress and Deformation Behaviors of a Deep and Irregular Foundation Pit as the Shield Launching Shaft in a Sea Reclaimed Cofferdam北大核心CSCD

With the development of the tunnel technology in China, the shield tunnel will become an important way to build the Sea-crossing channel. Taking the current largest diameter Shantou Bay shield tunnel in China as the engineering background, this paper introduces the challenges faced by the construction of the shield launching shaft in the reclamation cofferdam: e.g. deep, irregular excavation, deep silt layer and great influence of the seawater. Based on the practical conditions, a top-down construction technique of large ring beam considering two working conditions of foundation pit excavation and shield launching is proposed. Based on three-dimensional finite element analysis and field measurement, the stress characteristics and soil deformation of foundation pit are studied. The results show that the top-down construction technique of large ring beam can effectively control the deformation of the foundation pit and save construction time. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Study on Reinforcing Technology System for the Overlapped Running Shield Tunnels underneath the Track Group of High Speed Railways北大核心CSCD

The large settlements of tracks will emerge due to multiple disturbances in the construction of over- lapped shield tunnels, which affects the running safety of trains. Based on the overlapped Sungang station-Honghu station shield running tunnels of Shenzhen Metro line 7 passing underneath 26 tracks of high speed railways, a rein- forcement technology system consisting of”track support + subgrade reinforcement + interlayer soil consolidation + internal support of the lower tunnel”was developed. The settlements of tracks were mainly monitored automatically with manual monitoring as an auxiliary one. The results show that the maximum settlement of main track caused by constructing overlapped shield tunnels is -5.9 mm which is less than the control value of 10 mm, ensuring the opera- tion safety and verifying the reliability and practicability of the reinforcement technology system. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Effect of WO<Subscript>3</Subscript> nanoparticle loading on the microstructural,mechanical and corrosion resistance of Zn matrix/TiO<Subscript>2</Subscript>-WO<Subscript>3</Subscript> nanocomposite coatings for marine application

In this study, for marine application purposes, we evaluated the effect of process parameter and particle loading on the microstructure, mechanical reinforcement and corrosion resistance properties of a Zn-TiO₂-WO₃ nanocomposite produced via electrodeposition. We characterized the morphological properties of the composite coatings with a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS). We carried out mechanical examination using a Dura Scan hardness tester and a CERT UMT-2 multi-functional tribological tester. We evaluated the corrosion properties by linear polarization in 3.5% NaCl. The results show that the coatings exhibited good stability and the quantitative particle loading greatly enhanced the structural and morphological properties, hardness behavior and corrosion resistance of the coatings. We observed the precipitation of this alloy on steel is greatly influenced by the composite characteristics.