Welcome to the August 2014 issue of Transport, which covers a range of interesting subjects from the transport industry. The six papers in this issue address excavation and construction planning, pollution/safety and hazards, mathematical and statistical modelling, and traffic engineering.
These subjects contribute to the well-known fact that transportation technology provides considerable advantages to society. In some cases, however, negative impacts can arise if the application of these technologies does not take into consideration their effects on large cities, predominantly downtown areas, in terms of environment protection, traffic congestion and pollution. The elimination or mitigation of these negative impacts is of considerable concern to universities, researchers and the transportation industry in general. It is more difficult to remedy problems that have occurred than it is to prevent them occurring. This is a typical condition of large cities, predominantly, in developing countries.
The success of any engineering construction depends on close coordination among the parties invoved in the planning process. In this regard, the interaction and the creation of a good interface among designers, constructors and supervisors is crucial. When these interfaces are well established, hazard identification and risk management become achievable and efficient, resulting in acceptable levels of safety for the construction itself, surrounding installations, the environment and those using and living near it. No less important is compliance with the regulations, which will contribute markedly to environment protection.
An effective combination of all these aspects, during the construction of the King's Cross northern ticket hall, in London, UK, can be appreciated in the first paper of this issue (Worthington and Awinda, 2014). The authors describe how meticulous construction planning was put in place and how hazard identification and risk management were taken into account. They also show the exceptional preoccupation with the environment, water and air quality control and compliance with local regulations during the different stages of the construction. Interesting lessons can be learnt from this paper.
Hazardous materials (hazmat) are always a great concern to any transportation management system. Incidents or accidents that may occur during hazmat transportation can have a tremendous impact on people and on the environment. Furthermore, this is a topic that always benefits from studies and research focusing on the prevention and/or mitigation of the consequences of these types of incidents. The only way to overcome this challenge is to implement an efficient transportation management programme. This is the objective of the second paper, by Zhao et al. (2014), which describes how the Chinese authorities focus on this matter in relation to the railway system; the authors emphasise how important incident reports are to enhancing safety.
The third paper, by Mai et al. (2014), focuses on short-term traffic-flow forecasting (STTF), which allows for the prediction of short-term future traffic conditions based on current and past observations. The study suggests a new model based on real traffic volume observed at junctions located in the downtown area of Dublin, Ireland. Such data are a good basis on which to forecast real-time traffic flow at multiple junctions.
Following on from Mai et al., Thankappan and Vanajakshi (2014) address the theme of traffic stream, a subject that has been studied since the 1930s. The authors explore new ways to investigate the speed–flow–density relationship for non-homogeneous traffic conditions, in India. Most existing stream models were developed more than 10 years ago and, currently, are not fit for purpose considering the remarkable change in the traffic pattern in India. The traffic data were collected from one direction of a six-lane roadway at 1 min intervals. The results demonstrate that the models obtained are adequate for the traffic heterogeneity found in India.
Beginning in the 1910s, scientists and researchers have been studying how to deal with two-level interchanging roads (cloverleaf interchanges). Conventional spiral curves and compound curves are the two approaches considered in the fifth paper, by Mansourkhaki and Ghanad (2014), for geometric design of loop-ramp for cloverleaf interchanges. The authors suggest a new methodology for designing loop-ramps, using compound curves, aiming at reducing the time taken to run the entire process. Their new methodology indicates a considerable time saving.
The final paper, by Amir-Ansari (2014), provides an overview of how strategies implemented by the Tehran Traffic Authority, considering the peculiarities of that city, contributed to reducing traffic congestion, to decreasing the level of pollution and to improving traffic flow. Rapid population growth and the increase in the number of vehicles, mainly due to a massive marketing that stimulated demand, are the two factors identified as the origin of the problems.
Discussion of these papers is warmly welcomed by the Transport editorial advisory panel.
Please, visit the ICE Virtual Library (http://www.icevirtual library.com) to access the latest papers including those articles published ahead of print online.
