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91.
Comment by John R. Clark Comment by Kem Lowry Comment by Stephen B. Olsen Response by Jens Sorensen 相似文献
92.
Coastal lands provide popular outdoor recreation opportunities including beach recreation, fishing, boating, and wildlife viewing. Published studies measuring the demand for access to coastal lands generally have focused on the recreational value of intensively used beaches, which comprise only a portion of the New England coastline. This article examines the recreational demand for coastal access to a local, free‐access site in southern New England. The study uses data obtained from on‐site interviews conducted during the summer of 1995 at Gooseberry Island, Massachusetts. The estimated average value of a visitor‐day during the summer season is $3.06 for weekdays and $4.18 for weekends and holidays. While these values are at the low end of the range of values published in existing literature addressing beach recreation, the aggregate value of recreation benefits derived from public access to undeveloped coastal areas likely are significant. 相似文献
93.
94.
Automated detection of lane-blocking freeway incidents using artificial neural networks 总被引:2,自引:0,他引:2
A major source of urban freeway delay in the U.S. is non-recurring congestion caused by incidents. The automated detection of incidents is an important function of a freeway traffic management center. A number of incident detection algorithms, using inductive loop data as input, have been developed over the past several decades, and a few of them are being deployed at urban freeway systems in major cities. These algorithms have shown varying degrees of success in their detection performance. In this paper, we present a new incident detection technique based on artificial neural networks (ANNs). Three types of neural network models, namely the multi-layer feedforward (MLF), the self-organizing feature map (SOFM) and adaptive resonance theory 2 (ART2), were developed to classify traffic surveillance data obtained from loop detectors, with the objective of using the classified output to detect lane-blocking freeway incidents. The models were developed with simulation data from a study site and tested with both simulation and field data at the same site. The MLF was found to have the highest potential, among the three ANNs, to achieve a better incident detection performance. The MLF was also tested with limited field data collected from three other freeway locations to explore its transferability. Our results and analyzes with data from the study site as well as the three test sites have shown that the MLF consistently detected most of the lane-blocking incidents and typically gave a false alarm rate lower than the California, McMaster and Minnesota algorithms currently in use. 相似文献
95.
96.
Gerard de Jong Andrew Daly Marits Pieters Stephen Miller Ronald Plasmeijer Frank Hofman 《Transportation》2007,34(4):375-395
This paper provides a review of transport model applications that not only provide a central traffic forecast (or forecasts
for a few scenarios), but also quantify the uncertainty in the traffic forecasts in the form of a confidence interval or related
measures. Both uncertainty that results from using uncertain inputs (e.g. on income) and uncertainty in the model itself are
treated. The paper goes on to describe the methods used and the results obtained for a case study in quantifying uncertainty
in traffic forecasts in The Netherlands.
相似文献
Gerard de JongEmail: |
97.
Stephen Skippon Shoba Veeraraghavan Hongrui Ma Paul Gadd Nigel Tait 《Transportation Research Part A: Policy and Practice》2012,46(9):1405-1423
Global temperature rise over the long term will be proportional to the total amount of CO2 emitted. Any given probability of exceeding a targeted maximum temperature rise implies a maximum limit on the cumulative total of CO2 that can be emitted: a CO2 “budget”. This paper describes an approach to modelling cumulative emissions from light and heavy duty road transport from the present to 2050, focussing on the USA and Europe, and comparing the potential impacts of a range of technological and behaviourally-based abatement measures with such cumulative emissions budgets.The model shows that abatement measures would have a lower effect on cumulative emissions from 2000 to 2050 than on annual emissions in 2050, so that focussing only on annual emissions could be misleading. It shows that technological developments would be insufficient on their own to enable Europe and the USA to meet CO2 budgets for road transport. Behavioural changes, which potentially can be implemented much sooner, would be essential too. There is potential to keep European light duty emissions very close to CO2 budgets, and US light duty emissions not far above the least restrictive budget, but the model predicts that heavy duty emissions in both regions are likely to exceed their CO2 budgets. Deeper emissions reductions in other regions and sectors will be needed to compensate for this. Timing would be critical: for the greatest impact, behaviour change policies and interventions would need to be applied early and deeply. 相似文献
98.
Stephen Roberts 《Maritime Policy and Management》2000,27(3):253-265
The decline of the British merchant fleet in recent years has led to an increasing proportion of British seafarers taking employment in flags of convenience and other foreign-registered vessels. It is then a matter of some importance as to whether the British seafarers who serve in foreign ships are at greater risk of mortality and, when fatalities do occur, whether the deaths are appropriately investigated. Using information obtained from files at the Registrar General for Shipping, the Marine Accident Investigation Branch and many Coroners, it is evident that British seafarers serving in foreign vessels were, during the study period 1986-1995, at greater risk of mortality through work-related accidents, suicides and unexplained disappearances at sea. Those serving in the British fleet, however, died more frequently through illnesses, and through off-duty accidents and drowning. When fatalities occurred in the British fleet, the relevant log book extracts were routinely deposited with the appropriate British authorities; for deaths in FOC vessels these documents were rarely forthcoming. While the deaths of British seafarers were investigated in the large majority of cases, foreign flag state authorities seldom conducted inquiries; it was the British authorities who usually conducted the investigations. 相似文献
99.
Stephen Ison 《运输评论》2013,33(2):109-126
Cambridge is a small free standing city in the UK with a population of 105 000. In recent years it has endured a worsening congestion problem essentially as a result of employment growth within the city and the narrow street layout. This is not a unique problem but one which is particularly acute in historic cities. In 1990, Congestion Metering was advanced, in addition to a number of other measures, as a means of managing traffic demand within the city. It has generated a great deal of interest internationally, particularly the field trial which took place in October 1993. This was the first time that any form of road pricing had been demonstrated practically in the UK. The aim of this article is to provide a review, establishing why the idea of Congestion Metering was originally considered and why, at least in the short to medium term, it is unlikely to be implemented in a Cambridge context. The process by which, if adopted, it is envisaged that Congestion Metering would be introduced is outlined, and the relative merits and potential weaknesses of such a demand management measure. Finally, the author considers the real problem of ‘public scepticism’ which needs to be addressed if Congestion Metering is to avoid the pitfalls which have bedevilled other road pricing schemes world‐wide. 相似文献
100.
Reduced private car use can limit greenhouse gas emissions and improve public health. It is unclear, however, how promotion of alternative transport choices can be optimised. A systematic review and meta-analysis was conducted to identify potentially modifiable cognitive mechanisms that have been related to car use and use of alternative transport modes. A qualitative synthesis of measures of potentially modifiable mechanisms based on 43 studies yielded 26 conceptually distinct mechanism categories. Meta-analyses of associations between these mechanisms and car use/non-use generated 205 effects sizes (Pearson’s r) from 35 studies. The strongest correlates of car use were intentions, perceived behavioural control, attitudes and habit. The strongest correlates of alternative transportation choices were intentions, perceived behavioural control and attitudes. Implications for researchers and policy implementation are discussed. 相似文献