3,040 research outputs found
Speed limit enforcement as perceived by offenders: Implications for roads policing
Copyright@ 2010 The Authors. This is the post-print version of the article. The final published version may be accessed at the link below.Getting caught for speeding is an emotive issue. This paper analyzes an unexpected source of data captured by unprompted comments left at the end of a questionnaire by a sample of British drivers who all had penalty points on their licences, many for speeding.The paperâs relevance to roads policing is that perceived fairness of police procedures is crucial in shaping public support, and comments made by this sample of offending drivers indicated that speed limit enforcement through the operation of the speed camera system was often seen as unfair. Since roads policing is closely linked with this and with many drivers having penalty points on their licences, the views of such drivers could be instructive, given the continuing reliance on camera technology and the need for police to offer public reassurance. Finally, the implications for roads policing are considered.The data used in this paper are derived from a study funded by the Department for Transport (DfT)
Probing the Electrostatics of Integer Quantum Hall Edges with Momentum-Resolved Tunnel Spectroscopy
We present measurements of momentum-resolved magneto-tunneling from a
perpendicular two-dimensional (2D) contact into integer quantum Hall (QH) edges
at a sharp edge potential created by cleaved edge overgrowth. Resonances in the
tunnel conductance correspond to coincidences of electronic states of the QH
edge and the 2D contact in energy-momentum space. With this dispersion relation
reflecting the potential distribution at the edge we can directly measure the
band bending at our cleaved edge under the influence of an external voltage
bias. At finite bias we observe significant deviations from the flat-band
condition in agreement with self-consistent calculations of the edge potential
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Does the threat of disqualification deter drivers from speeding?
Road Safety Research Report, number 96, is available from the National Archives: Department for Transport, and can be accessed from the link below.It has long been recognised that driving speeds that are excessive and inappropriate
to the conditions are a major contributory factor in road accidents, and a major issue
for road safety. Restraining driving speeds has proved to be a difficult task, given the
improvements over the years in both vehicle performance and road design.
Within the traditional âthree Esâ countermeasures of engineering, education and
enforcement, recent years have seen the introduction of a wide range of engineering
measures designed to bring about speed reduction, but these tend to be restricted to
specific parts of the road network. New technologies such as Intelligent Speed
Adaptation (ISA) offer considerable promise, but mainly in the medium or longer term. Similarly, educative efforts to induce attitude and behaviour change in this context are bearing fruit, yet this is a long-term rather than short-term project. For the foreseeable future, enforcement will remain the principal means of influencing speed, by setting speed limits and imposing sanctions on drivers who are caught exceeding them.
The number of licence endorsements has increased enormously in recent years.
However, over the same period the number of disqualifications resulting from âtotting-upâ points has decreased. This would seem to indicate that many drivers who accumulate up to 11 penalty points are either acting as if deterred by the threat of disqualification, or are avoiding disqualification in some other way. The extent to which penalty points act as a deterrent for the benefit of road safety in general is therefore an important issue, and this report describes work that has been carried out to study this issue by TRL and Brunel University, under contract to the Department for Transport
Corner overgrowth: Bending a high mobility two-dimensional electron system by 90 degrees
Introducing an epitaxial growth technique called corner overgrowth, we
fabricate a quantum confinement structure consisting of a high-mobility
GaAs/AlGaAs heterojunction overgrown on top of an ex-situ cleaved substrate
corner. The resulting corner-junction quantum-well heterostructure effectively
bends a two-dimensional electron system (2DES) at an atomically sharp angle. The high-mobility 2DES demonstrates fractional quantum Hall effect
on both facets. Lossless edge-channel conduction over the corner confirms a
continuum of 2D electrons across the junction, consistent with
Schroedinger-Poisson calculations of the electron distribution. This growth
technique differs distinctly from cleaved-edge overgrowth and enables a
complementary class of new embedded quantum heterostructures.Comment: 3 pages, 4 figures, latest version accepted to AP
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