Organization of urban mass transport in developing countries

The supply of mass transport has not kept pace with the demand in cities in developing countries due to rapid urbanization and severe resource constraints. Developing countries would benefit from a study of the experience in developed countries regarding organization of mass transport and may adopt a few of the successful techniques. Examples include: unified transport authority; intermodal transfer facilities; subsidy to public transport; light rail transit; and redevelopment of the area around main rail terminals. Developing countries would be able to implement most of these techniques. The possible contribution of developed countries to developing countries lies mainly in the area of rolling stock and advanced signalling for rail based urban transport and in training highly skilled manpower for operation and management.     

Possibility of jamming and wedging in the three-piece trucks of a moving freight car

Three-piece trucks have some drawbacks, particularly unstable operation of the friction wedge damping system. One of the principal features of systems of this kind is the possibility of jamming and wedging. This work is devoted to mathematical and numerical modeling of the plane motion of a freight car with allowance for the mobility of the wedges and then for the compliance of the contacting bodies and to the study of the conditions for the onset of jamming and wedging when the car is in motion.     

Incentivizing alternative fuel vehicles: the influence of transport policies,attitudes and perceptions

This paper aims to evaluate the influence of policies, attitudes and perceptions when incentivizing alternative fuel vehicles. The impact of possible policies such as gasoline taxes increases, purchase price subsidies, tax exemptions, and increases in fuel recharging station availability for alternative fuelled vehicles is evaluated using hybrid choice models. The models also allow assessing the sensitivity of latent variables (i.e., attitudes and perceptions) in the car purchase behaviour. The models are estimated using data from a stated choice survey collected in five Colombian cities. The latent variables are obtained from the rating of statements related to the transport system, environmental concern, vehicle preferences, and technology. The modelling approach includes regression between latent variables. Results show that environmental concern and the support for green transport policies have a positive influence on the intention to purchase alternative fuel vehicles. Meanwhile, people who reveal to be car-dependent prefer to buy standard fuelled vehicles. The analysis among cities shows similar trends in individual behaviour, although there are differences in attribute sensitivities. The policy scenario analysis revealed high sensitivity to capital cost and the need for extensive investments in refuelling stations for alternative fuel vehicles to become attractive. Nevertheless, all policies should not only be directed at infrastructure and vehicles but also be focused on user awareness and acceptance of the alternative fuel vehicles. The analysis suggests that in an environmentally conscious market, people prefer alternative fuels. However, if the transport policies support private transport, the market shares of alternative fuel vehicles will decrease.     

Adaptive data dissemination for time-constrained messages in dynamic vehicular networks

With the advent of emerging wireless communication technologies, tremendous efforts have been put on promoting the safety and efficiency of transportation services by developing innovative applications. In particular, there has been significant interest in accessing information stored at RSUs (Roadside Units). The unique characteristics in vehicular networks, such as dynamic traffic factors including vehicle arrival rate, dwell time and data access patterns, bring us new challenges on data dissemination. This work dedicates to the investigation of timely and adaptive data dissemination in the dynamically changing traffic environment. Firstly, we derive an analytical model to explore and examine the effects of the dynamic traffic factors. In light of the theoretical results, an on-line scheduling algorithm is proposed for adaptive data dissemination. Finally, we evaluate performance of the new algorithm in a variety of circumstances. The simulation results demonstrate satisfactory performance of the proposed algorithm.     

Upstream transport corridor inefficiencies and the implications for port performance: a case analysis of Mombasa Port and the Northern Corridor

The role of efficient ports in the socio-economic prosperity of national and regional economies cannot be overstated. However, their ability to effectively deliver on this role is easily undermined by circumstances in the wider socio-economic context, particularly poor hinterland connectivity. In order to enhance international trade connectivity, many advanced and advancing economies continue to invest significant resources in developing efficient ports and hinterland transport networks. The situation is different in many parts of the developing world, particularly Africa, where poor economic connectivity and inefficient gateway ports result in prohibitively high transportation costs. Focusing on the northern trade and transport corridor in the East and Southern Africa (ESA) region, this article examines how poor hinterland connectivity undermines the performance of Mombasa port. It concludes that, although the port’s management has in recent years invested significantly in performance-enhancing initiatives, their success is limited by a constricted economic environment that is characterised by poor hinterland connectivity and chronic logistics bottlenecks along the arterial corridor.     

What determines university student’s willingness to pay for bikeways?

Transportation - Inadequate infrastructure is recognized as an important barrier to cycling; therefore, improvements in the provision of bicycle facilities, such as bikeways, are frequently...     

Implications of Thresholds in Discrete Choice Modelling

Abstract

Individual choices are affected by complex factors and the challenge consists of how to incorporate these factors in order to improve the realism of the modelling work. The presence of limits, cut‐offs or thresholds in the perception and appraisal of both attributes and alternatives is part of the complexity inherent to choice‐making behaviour. The paper considers the existence of thresholds in three contexts: inertia (habit or reluctance to change), minimum perceptible changes in attribute values, and as a mechanism for accepting or rejecting alternatives. It discusses the more relevant approaches in modelling these types of thresholds and analyses their implications in model estimation and forecasting using both synthetic and real databanks. It is clear from the analysis that if thresholds exist but are not considered, the estimated models will be biased and may produce significant errors in prediction. Fortunately, there are practical methods to attack this problem and some are demonstrated.     

Transition between Signal Timing Plans: A Methodological and Analytical Overview

Abstract

The transition phase is generally defined as the process of switching from one timing plan to another; this process may include changes in offset, phase split or cycle length until coordination for a new timing plan is reached once again. As noted in the literature, transition phases between timing plans may lead to severe disruptions of traffic flow, resulting in potentially lasting effects. The aim of this paper is to comprehensively review, classify and analyse the literature regarding transition between different timing plans to highlight existing research gaps and give researchers a starting point to continue contributing with solutions to the transition problem. Regarding transition approaches, a gap concerning mathematical approaches was deemed significant as a transition could be greatly benefited by simultaneously optimising more than one operational measure of effectiveness through multi-objective mathematical models. Moreover, in the analysis of applied approaches, Shortway algorithms generally outperformed other practical methods under different scenarios.     

Assessing the influence of indicators’ complexity on hybrid discrete choice model estimates

Transportation - Hybrid discrete choice (HDC) modeling requires indicators to allow for the identification of latent variables. An indicator usually expresses the level of agreement of a respondent...