Traffic accident risk perception among drivers: a latent variable approach

ABSTRACT

Governments require decision tools to deal with road traffic accidents, a pandemic resulting in millions of deaths around the world. Evidence shows that human factors are one of the major causes of road accidents, and there is much interest in identifying variables that may have an impact on drivers’ perception of risk. To this aim, we design a stated choice experiment with eight hypothetical driving scenarios considering attributes that have been strongly associated with increased accident risks: (i) driving speed, (ii) driving the wrong way in a one-way street, (iii) overtaking on a bend, and (iv) driving under the influence of alcohol or drugs. Data from a sample of survey respondents are used to estimate a hybrid discrete choice model incorporating two latent variables, Driver Concentration and Safe Driving. Our results may contribute to the design of public policies geared to prevent accidents by encouraging safer driving behaviour.     

Addressing endogeneity in strategic urban mode choice models

Transportation - Endogeneity is a potential anomaly in econometric models, which may cause inconsistent parameter estimates. Transport models are prone to this problem and applications that...     

Multi-fidelity optimization of a high-speed foil-assisted semi-planing catamaran for low wake

The wakes of high-speed passenger-only ferries that operated through Rich Passage, on the Seattle-Bremerton ferry route, caused beach erosion and damage to habitat. A task was initiated to design a low-wake high-speed vessel using multi-fidelity CFD based design optimization by using low-fidelity potential flow solvers for initial global design optimization and by using URANS solvers for high-fidelity tuning of the optimized design. This simulation based design process involved a close collaboration between ship designers, and hydrodynamics and CFD specialists, whose collective expertise guided the evolution of the design based on both hydrodynamic and structural aspects. The initial hull shape optimization using potential flow code was carried out by blending three different initial concepts provided by the designers. Subsequently, URANS was used to evaluate the potential flow optimized hull and to further optimize the hull configuration parameters, namely, the centre-of-gravity, demihull spacing, foil location, foil angle and slenderness ratio at different displacement conditions. The URANS based configuration optimization also took into account the far field wakes’ energy spectrum with an objective of reducing the energetic, low frequency far field wakes which are associated with beach flattening on the mixed sand and gravel beaches. Calculation of the far field wake using URANS would require an unfeasibly large domain size; therefore, a Havelock code with a source distribution matching the URANS calculated near field wave elevation was used to propagate the wakes into the far field. The end result of the optimization was a design with significantly reduced far field wake, which is currently being built for experimental testing.     

Traffic congestion pricing methodologies and technologies

This paper reviews the methods and technologies for congestion pricing of roads. Congestion tolls can be implemented at scales ranging from individual lanes on single links to national road networks. Tolls can be differentiated by time of day, road type and vehicle characteristics, and even set in real time according to current traffic conditions. Conventional toll booths have largely given way to electronic toll collection technologies. The main technology categories are roadside-only systems employing digital photography, tag & beacon systems that use short-range microwave technology, and in-vehicle-only systems based on either satellite or cellular network communications. The best technology choice depends on the application. The rate at which congestion pricing is implemented, and its ultimate scope, will depend on what technology is used and on what other functions and services it can perform.     

Global ship risk profiles: Safety and the marine environment

This article uses visualization techniques to investigate global ship risk profiles and their changes over time. With a unique data set of 49,151 observations, the authors link changes in risk profiles to legislative developments and industry actions, as well as identify areas prone to general safety, loss of life, and pollution risks. Improved risk profiles over time have resulted from legislative measures, including the International Safety Management Code, the Oil Pollution Act, amendments to the International Convention for the Prevention of Pollution from Ships, and the introduction of port state controls and industry vetting inspections.     

谈施工安全控制

分析了常见施工安全事故的特征及事故发生的原因，并结合多年的施工经验，介绍如何控制和保障施工安全的经验和体会。     

车用稀燃增压单一燃料CNG发动机电控系统的研究

为深入研究 CNG发动机稀薄燃烧特性 ,进一步降低天然气发动机的有害排放 ,设计了车用增压天然气发动机电控系统。该系统采用高能点火模块来获得天然气着火所需的点火能量 ,电控喷射单元采用模糊控制器来获得比较精确的空燃比控制 ,实现对天然气发动机的顺序多点喷射。运用该系统对增压单一燃料 CNG发动机的燃烧和排放性能进行了试验研究 ,结果表明了该系统的有效性。     

Real-time capable vehicle-trailer coupling by algorithms for differential-algebraic equations

The real-time simulation of vehicle trains requires an accurate and numerically feasible representation of the vehicle-trailer coupling. Although the equations of motion for the chassis instances can be reduced to systems of ordinary differential equations, additional constraints on the relative motion of vehicle and trailer are introduced when considering the hitch. In this article, we present a strategy for the simulation of vehicle-trailer combinations, where the algebraic constraints of the coupling are treated explicitly. Although this approach allows exact modeling of the respective joint geometry and realistic calculation of the coupling forces, a suitable numerical algorithm is required in order to solve the resulting differential-algebraic system of index 3 in real-time. The implementation in a commercial vehicle dynamics program is discussed and real-time simulation results are shown, which prove its feasibility for different coupling joints and demanding driving maneuvers.     

Analysing training and education in ports

The quality and availability of labour is important for the performance of ports. Insights from cluster theories are relevant for analysing training and education in ports, as ports can be regarded as clusters. In general, labour in clusters is relatively mobile, education services in clusters are relatively good and employees have a high willingness to invest in specific skills. However, skilled and talented labour still may be scarce, especially in regions with tight labour markets. Thus, in many clusters, including port clusters, firms and governments actively aim to improve the quality of labour. This paper presents an analysis of these efforts of firms and governments to improve the quality of the labour force in three seaport clusters. In this paper the concept of a ‘training and education regime’ is presented as an approach to analyse efforts of firms and governments to improve the quality and availability of labour. Important results of three case studies include first, the observation that the quality of training and education regime differs substantially between clusters. Second, the presence of aregime manager in Rotterdam adds to the quality of Rotterdam’s training and education regime. Such an organisation may be effective across countries and clusters. Finally, the presence ofleader firms, willing to invest in training and education also improves an education regime.     

The <Emphasis Type="Italic">Santiago Panel</Emphasis>: measuring the effects of implementing Transantiago

Although panels offer significant advantages over cross sectional data especially in terms of evaluating the effects of significant policy changes, there are precious few examples of panels built around an important change to an urban transport system. For this reason we took the opportunity of the introduction of Transantiago, a radically new public transport system for Santiago de Chile in February 2007, to form a panel, the first wave of which was taken in December 2006. The final objective was to use this Santiago Panel to estimate mode choice models considering both inertia and policy effects. This document describes both the design and construction of the panel, and presents some results based on an analysis of its four waves; for example, we registered a high percentage of mode change (55.1%) attributable to the introduction of the new system. The panel can claim the highest response rate (or lowest attrition) reported in the literature (95% in the second wave, 92% in the third one, and 85% in the forth one). This hints at the possibility of developing sophisticated models to evaluate the effects of a system shock in the presence of inertia in decision making.