A behavioral choice model of the use of car-sharing and ride-sourcing services

There are a number of disruptive mobility services that are increasingly finding their way into the marketplace. Two key examples of such services are car-sharing services and ride-sourcing services. In an effort to better understand the influence of various exogenous socio-economic and demographic variables on the frequency of use of ride-sourcing and car-sharing services, this paper presents a bivariate ordered probit model estimated on a survey data set derived from the 2014–2015 Puget Sound Regional Travel Study. Model estimation results show that users of these services tend to be young, well-educated, higher-income, working individuals residing in higher-density areas. There are significant interaction effects reflecting the influence of children and the built environment on disruptive mobility service usage. The model developed in this paper provides key insights into factors affecting market penetration of these services, and can be integrated in larger travel forecasting model systems to better predict the adoption and use of mobility-on-demand services.     

The impact of automated transit,pedestrian, and bicycling facilities on urban travel patterns

This article reports on an integrated modeling exercise, conducted on behalf of the US Federal Highway Administration, on the potential for frequent automated transit shuttles (‘community transit’), in conjunction with improvements to the walking and cycling environment, to overcome the last-mile problem of regional rail transit and thereby divert travelers away from car use. A set of interlocking investigations was undertaken, including development of urban visualizations, distribution of a home-based survey supporting a stated-preference model of mode choice, development of an agent-based model, and alignment of the mode-choice and agent-based models. The investigations were designed to produce best-case estimates of the impact of community transit and ancillary improvements in reducing car use. The models in combination suggested significant potential to divert drivers, especially in areas that were relatively transit-poor to begin with.     

Optimal distribution of financial incentives to foster off-hour deliveries in urban areas

The main objective of this paper is to develop mathematical formulations to gain insight into the best way to distribute financial incentives to receivers of urban deliveries to maximize participation in off-hour deliveries. The paper considers two different types of incentive budgets: exogenous, and endogenous. The exogenous case represents the condition in which an external decision maker determines the incentive budget that is to be distributed among potential participants in off-hour deliveries. In the case of an endogenous incentive budget, the entity distributing the incentives must raise the necessary funds using revenue generation mechanisms such as tolls and fines. The optimal incentives are obtained from the Karush–Kuhn–Tucker conditions of a mathematical program that maximizes the number of truck trips shifted to the off-hours as a function of the incentives. The mathematical models developed in this paper provide guidelines about how to optimally distribute financial incentives to foster off-hour deliveries.     

How does travel satisfaction sum up? An exploratory analysis in decomposing the door-to-door experience for multimodal trips

Transportation - Understanding how satisfaction with individual trip legs aggregates to the overall travel experience for different types of trips will enable the identification of the trip legs...     

Manoeuvring and hotelling external costs: enough for alternative energy sources?

Local air pollution is the most relevant externality of maritime transport, and its effects are more acute in urban areas as a result of manoeuvring, hotelling and load/unload activities at ports. This article is intended to assess ships’ local air pollution impact in generally densely populated harbour areas to decide whether alternative power supply measures are feasible. First, an optimized infrastructure investment model is developed to ease implementation and maximize the efficiency of alternative power supply projects. Once target harbours and traffic (ship types) within a national port network have been chosen, a vessel traffic analysis (ship type, tonnage, manoeuvring, and hotelling times) is carried out to quantify and evaluate annual polluting emissions (PM_2,5, SO₂, NOx, and VOCs) and their externalities. Finally, the assessment model is applied and results of the Spanish port network case study are discussed. The results obtained are significant and bring the possibility of further controlling the ship’s environmental performance at berth.     

Actively translating a rear diffuser device for the aerodynamic drag reduction of a passenger car

This research aims to develop an actively translating rear diffuser device to reduce the aerodynamic drag experienced by passenger cars. One of the features of the device is that it is ordinarily hidden under the rear bumper but slips out backward only under high-speed driving conditions. In this study, a movable arc-shaped semi-diffuser device, round in form, is designed to maintain the streamlined automobile??s rear underbody configuration. The device is installed in the rear bumper section of a passenger car. Seven types of rear diffuser devices whose positions and protrusive lengths and widths are different (with the basic shape being identical) were installed, and Computational Fluid Dynamics (CFD) analyses were performed under moving ground and rotating wheel conditions. The main purpose of this study is to explain the aerodynamic drag reduction mechanism of a passenger car cruising at high speed via an actively translating rear diffuser device. The base pressure of the passenger car is increased by deploying the rear diffuser device, which then prevents the low-pressure air coming through the underbody from directly soaring up to the rear surface of the trunk. At the same time, the device generates a diffusing process that lowers the velocity but raises the pressure of the underbody flow, bringing about aerodynamic drag reduction. Finally, the automobile??s aerodynamic drag is reduced by an average of more than 4%, which helps to improve the constant speed fuel efficiency by approximately 2% at a range of driving speeds exceeding 70 km/h.     

Dynamics analysis of an omni-directional vehicle

In a modern society, traffic congestion is a major problem in every metropolis. To solve the problem of traffic congestion an innovative omni-directional vehicle is proposed. This research has mainly focussed on developing the comprehensive vehicle dynamics model for an omni-directional road vehicle. Then the stability of the vehicle in the yaw plane was analysed under different scenarios based on the response of the side slip angle. Finally an active steering PID controller was suggested and which, according to the results of the simulation, improved the yaw plane stability.     

Dynamic analysis of seatbelt systems with anti-inertial release mechanisms

In order to prevent the uncontrolled release of seatbelt buckles due to high acceleration caused by pretensioners, anti-g buckles that have pendulum-shaped g-masses to block the releasing motion are commonly adopted in seatbelt systems. However, even with the wide applications of anti-g buckles, the underlying operational principles of anti-g buckles have yet to be investigated. This work studies conditions for the engagement of the g-mass to prevent inertial release, and conditions for maintaining a blocked state under very high acceleration. Using a multibody model of an anti-g buckle, the effects of various design parameters on the performance of the anti-g buckle have been examined. It turns out that design variables associated with the geometry of the g-mass and its contacting surface configuration play important roles. In order to account for the dynamic interaction between driver and seatbelt, a multibody model of a seatbelt system is combined with a dummy model to form a single dynamic system. Using the measured displacement of the buckle during the explosion of a pretensioner as the driving condition for simulation, dynamic analysis of the seatbelt with driver interaction has been carried out. Through comparison with measured and computed accelerations of webbing, which shows good agreement, the validity of the model has been demonstrated. The dynamic model for seatbelt and driver can be used as a design tool for the development of anti-g buckles.     

铁路货车防盗系统设计

针对铁路运输的货物在途中被盗现象，提出了货车、集装箱防盗系统的设计原理，给出了系统硬件结构示意图和软件设计框图并对其在 Ｔ Ｍ Ｉ Ｓ中的使用前景进行了展望。