The management of the rural transportation problem in Nigeria

In spite of the fact that about 70% of Nigeria's population live in rural areas, these areas have remained largely inaccessible. Not only do they lack motorable roads and organized public transport but also field surveys indicate that nearly all rural inhabitants do not have a private car. A Directorate of Food, Roads and Rural Infrastructure has been set up to manage the inaccessibility problem, among others. Whereas there are several conventional approaches to the management of the rural transportation problem, the Nigerian approach relies on the provision of roads. This restrictive approach with an emphasis on locational to the neglect of personal accessibility has various limitations which are analysed.     

Transportation of hazardous materials on Arizona's low volume roads

This paper attempts to address the issue of transporting hazardous materials and the question whether this activity constitutes a significant problem on Arizona's low volume roads. Problems related to lack of data required for most of existing risk assessment models are discussed. A preliminary risk assessment, conducted by the use of a screening model, attested that of the total state low volume road mileage, only 30% may need further, and more detailed, hazardous materials transportation risk analysis. The remaining 70% is currently free of any significant risk.     

Evaluation of general aviation management at Denver Stapleton airport

The potential benefits of general aviation management at a major airport is examined in this paper. The three general aviation management techniques investigated are volume reduction, runway segregation and time restriction.

First, a methodology for analyzing these techniques is discussed. The various effects on each user group are quantified for economic comparison between each management technique attempted. A computer simulation model was used to measure the delay effects. Then, these techniques are applied to Denver Stapleton Airport to measure their effects in present and future scenarios.

The results show that the best general aviation management technique is volume restriction. The use of peak‐hour pricing mechanism provided better results than random rejection, particularly if only a small degree of diversion is desired. The construction of a new general aviation runway provided equivalent results to the best technique tested.     

Energy conservation and intercity freight transport

In this paper, the characteristics of intercity freight modal operations are investigated to evaluate the potential for achieving energy savings. It is determined that the greatest opportunities for conserving energy appear to rest with achieving modal shifts and operational improvements in truck and rail transport. To test this hypothesis, intercity truck and rail freight operations are analyzed to determine the relationships between energy consumption and the delivery of transport service. The energy consumption impact of alternative conservation measures are calculated, and in turn, evaluated in light of a series of institutional constraints. As such, this study goes beyond the characteristic cataloging of alternative energy conservation measures by conducting a disaggregated assessment of the effectiveness and feasibility of implementing such measures. This paper concludes that the potential for achieving energy conservation in the movement of intercity freight in general, and by truck and rail systems in particular, is limited, as well as shrouded by the complexity of the nature of the commodity itself, the commodity flow characteristics, and the market and institutional structure.     

Formal scientific research of traffic collision data utilizing GIS

This paper explores the tenuous link between speeding behavior and accident causation, one that has not been well established in the international literature to date. Taking advantage of established engineering conventions and formulae, we were able to set up an a priori hypothesis suitable for testing. Utilizing this formal scientific method (which GIS researchers have been criticised for not using) we establish a statistical link for this relationship. Our methodology can be used to support all police intervention strategies, including the controversial photo radar systems. The results from our research have been entered into a GIS in order to create a map for spatial display. This map illustrates the relative probability or risk of collision occurrence resulting from speeding at all intersections and interchanges within the scope of the study. It is suggested that this methodology could easily be maintained with periodic updates of data, thus creating a dynamic model from which to monitor traffic safety within the city. Furthermore, this model can be utilized to study specific strategies, allowing for the scrutiny of before, during and after effects. The study area is the entire city of Calgary, Alberta, Canada, and includes all traffic collisions occurring during the year of 1994.     

大庆至广州高速公路河北段路线优化中

大广高速公路河北段路线长,地质条件十分复杂,在工程前期设计中通过对路线的优化,很好地解决了地基处理问题和环境保护问题,值得同行借鉴。     

底部薄板附近的水流及泥沙运动特性

通过水槽实验探讨了在饱和来沙条件下底部薄板附近的水流、泥沙运动特性,包括不同薄板高度、与水流不同夹角的安装方向等情况下,单个底部薄板附近的水流结构、泥沙运动规律、底部薄板的导沙特性及其附近的冲淤现象,以及底部薄板群体的导沙特性。试验结果表明,实验使用的薄板的长度对实验结果影响很大,过短的薄板实验根本观察不到薄板前冲刷沟内的沙波运动,而该沙波运动严重影响薄板的导沙效应。底部薄板附近的水流结构具有强烈的三维特性,流场复杂,对于一定的薄板,水流夹角、沙波的运动是影响薄板的导流导沙促淤的主要因素。     

New potential for multimodal connection: exploring the relationship between taxi and transit in New York City (NYC)

Transportation - Taxi trips have been somewhat neglected in transportation mobility and multimodal connection studies. The socio-demographic characteristics of taxi riders are often not fully...