Lights, camera and acoustics: Assessing macrobenthic communities at a dredged material disposal site off the North East coast of the UK

This study presents the results of a trial assessment based on a combination of sampling techniques at a dredged material disposal site located off the North East coast of the UK, over 2001 to 2004. The site was surveyed with a high-resolution sidescan sonar system producing a mosaic with 100% coverage of the survey area. Benthic communities and sediments were ground-truthed using a Hamon grab with a video camera. Additionally, the area was also sampled in 2003 with a Sediment Profile Imaging (SPI) camera, which complemented other techniques by providing in situ information on sediment quality, and biogenic activities. An assessment is made of the benefits of combining the results from conventional methods, principally using grab samples, with those from acoustic techniques and optical imaging devices to determine seafloor and macrobenthic conditions. This information has the potential to contribute to the enhancement of routine monitoring programmes within UK waters.     

法国GTT公司发布MarkIII薄膜型LNG船液舱制荡相关要求的更新

法国“货物维护系统”设计公司GTT宣布,对于MarkIII薄膜型LNG船液舱制荡低位注入液面高度限制的修订于三月中旬出台。GTT称新的低位注入液面高度限制将要求在液舱下部的1.5米注入货物。     

Passenger experience with quality-enhanced bus service: the tyne and wear ‘superoute’ services

This paper investigates the role that enhanced service quality introduced into a deregulated market has in improving the experience of bus travel by a sample of passengers in the Tyne and Wear area of England. A generalised ordered choice (GOC) model that accounts for preference heterogeneity through random parameters, as well as heteroscedasticity in unobserved variance, and random parameterisation of thresholds, is implemented to identify sources of influence on the overall experience of bus travel in the presence and absence of the quality-enhanced treatment of service. The GOC model is contrasted with a standard ordered logit model, and the marginal effects associated with the preferred GOC model are derived for each influencing attribute, taking into account the various ways in which each influence contributes to the utility associated with each level of bus experience. The paper supports a view that the introduction of quality improvements, via a Quality Bus Partnership, does contribute non-marginally to an increase in a positive bus experience, and signals a way forward through cooperative intervention, to grow patronage. Knowing which attributes successfully deliver a more positive experience (and those that do not) means that resources are effectively targeted at the aspect of service provision which will increase patronage and therefore revenues, satisfying the objectives of both the bus operator and the local authority partner.     

Estimating the willingness to pay and value of risk reduction for car occupants in the road environment

In recent years there has been a re-focus on the valuation of a statistical life from the ex post or human capital method to an ex ante willingness to pay (WTP) approach. This is in part a recognition that we may have been undervaluing the cost of fatalities and injuries to society associated with crashes, but also a strong belief in the need to focus on establishing the amount, ex ante, that individuals are willing to pay to reduce the risk of exposure to circumstances that might lead to death or degree of injury on the road network. This study has developed a framework in which to identify the degree of preference heterogeneity in willingness to pay by individuals who are drivers or passengers in cars to avoid being killed or injured. A stated choice experiment approach is developed. The empirical setting is a choice of route for a particular trip that a sample of individuals periodically undertakes in Australia. The particular trip is described in enough detail to provide the respondent with a familiar market environment, providing all the relevant background information required for making a decision. Mixed logit models are estimated to obtain the marginal (dis)utilities associated with each influence on the choice amongst the attribute packages offered in the stated choice scenarios. These estimates are used to obtain the WTP distributions for fatality and injury avoidance, which are then aggregated to obtain estimates of the value of risk reduction (VRR), of which the fatality class is also known as the value of a statistical life (VSL).     

To competitively tender or to negotiate - Weighing up the choices in a mature market

A key attribute of competitive tendering for the periodic selection of operators of subsidised public transport services is to secure the provision of specified services at efficient cost levels. This has proved particularly effective where services were previously provided by an inefficient monopoly operator. The arguments for the adoption of competitive tendering in preference to negotiation with the incumbent operator may be less clear-cut in other cases.Consideration is given to both theoretical and practical insights into the relative merits of competitive tendering and negotiation approaches in such situations. The limited literature on the topic is reviewed and insights and lessons identified. Influencing issues include prior conditions, the nature of the supplier market, features of contracts, negotiating and competitive tendering strategies and practice, accountability and transparency, and long-term market implications. The evidence suggests that ‘one size does not fit all’, and the choice will depend on specific circumstances.The relative merits of the two approaches for renewal of bus contracts are considered with regard to Adelaide, for contracts which have previously been awarded through competitive tendering. The paper draws out the main factors that could influence the authority’s choice between the options, and discusses the relevance of the findings to other situations.     

Estimation of trailer off-tracking using visual odometry

High-capacity vehicles have been shown to be highly effective in reducing emissions associated with road freight transport. However, the reduced manoeuvrability of long vehicles often necessitates the use of active trailer steering. Path-following trailer steering systems are very effective in this regard, but are currently limited to on-highway applications due to the manner in which trailer off-tracking is estimated. In this work, a novel trailer off-tracking measurement concept is introduced which is independent of wheel slip and ground surface conditions, and requires no additional sensor measurements or parameter data from the tractor. The concept utilises a stereo camera pair affixed to the trailer and a visual odometry-based algorithm to calculate off-tracking. The concept was evaluated in detailed simulation and full-scale vehicle tests, demonstrating its feasibility and highlighting some important characteristics. RMS measurement errors of 0.11–0.12?m (3.3–3.6%) were obtained in a challenging visual environment.     

Refocusing the Modelling of Freight Distribution: Development of an Economic-Based Framework to Evaluate Supply Chain Behaviour in Response to Congestion Charging

The distribution of freight is a major contributor to the levels of traffic congestion in cities. However it is much neglected in the research and planning activities of government, where the focus is disproportionately on passenger vehicle movements. Despite the recent recognition of the contribution of freight transportation to the performance of urban areas under the rubric of city logistics, we see a void in the study of how the stakeholders in the supply chain might cooperate through participation in distribution networks, to reduce the costs associated with traffic congestion. Given that transport costs are typically over 45 of all distribution costs, with congestion a major contributor in the urban setting, the importance of establishing ways in which supply chain partnerships might cooperate to reduce levels of freight vehicle movements has much merit. This paper sets out a framework to investigate how agents in a retail supply chain might interact more effectively to reduce the costs of urban freight distribution. We propose an interactive agency choice method as a way of formalising a framework for studying the preferences of participants in the supply chain to support specific policy initiatives. Such a framework is a powerful way of investigating the behavioural response of each agent to many policies, including congestion pricing, as a way of improving the efficient flow of traffic in cities.     

Do preferences for BRT and LRT change as a voter,citizen, tax payer,or self-interested resident?

Transportation - Interest in modal preferences remains a topic of high interest as governments make infrastructure decisions that often favour one mode over the other. An informative input into the...     

The evaluation of large cycling infrastructure investments in Glasgow using crowdsourced cycle data

Transportation - The benefits of cycling have been well established for several decades. It can improve public health and make cities more active and environmentally friendly. Due to the...