Examining the relationship between active travel,weather, and the built environment: a multilevel approach using a GPS-enhanced dataset

This study examines how the built environment and weather conditions influence the use of walking as a mode of transport. The Halifax Regional Municipality in Nova Scotia, Canada is the study area for this work. Data are derived from three sources: a socio-demographic questionnaire and a GPS-enhanced prompted recall time-use diary collected between April 2007 and May 2008 as part of the Halifax Space-Time Activity Research project, a daily meteorological summary from Environment Canada, and a comprehensive GIS dataset from the regional municipality. Two binary logit multilevel models are estimated to examine how the propensity to use walking is influenced by the built environment and weather while controlling for socio-demographic characteristics. The built environment is measured via five attributes in one model and a walkability index (derived from the five attributes) in the other. Weather conditions are shown to affect walking use in both models. Although the walkability index is significant, the results demonstrate that this significance is driven by specific attributes of the built environment—in the case of this study, population density and to a lesser extent, pedestrian infrastructure.     

Shorter sea routes as a result of increasing cargo flows

This paper examines the apparent paradox involved in shipping lines responding to increasing cargo flows from Britain to mainland Europe by moving to shorter routes. Analysis shows, however, this move to be a logical and valuable defensive response by shipping lines but at a cost to the transport consumer.     

Bus accidents,bus deregulation and London

Local bus services were deregulated in October 1986 in all areas of Britain except London. Government policy is to extend deregulation to London, though not in the current parliament. This paper analyses statistics on bus accidents from the national road accident database from 1981 to 1991 to compare results for London and the rest of Great Britain, and to consider whether deregulation has affected safety. The conclusions depend on the assumption that accident recording practice was not itself affected by deregulation.Bus accident rates are higher in London than on built-up roads elsewhere, partly apparently because of road traffic conditions in London, and partly because open-platform buses have higher accident rates involving occupants, including boarding and alighting accidents, than buses with doors.The main safety effects of deregulation operate through its effects on bus activity, though there is also some evidence that the rate per bus-kilometre of accidents involving other road users fell slightly. This may be due in part to the trend towards smaller buses associated with deregulation. Deregulation has led to a fall in bus patronage, and thus to a fall in occupant casualties; and to a rise in bus-kilometres, and thus to a rise in casualties among other road users in accidents involving buses. The number of fatal and serious casualties among other road users involved in bus accidents is larger than the number among bus occupants, so deregulation in London could lead on balance to a small rise in fatalities involving buses. On the other hand, the number of slight casualties among other road users involved in bus accidents is smaller than the number among bus occupants, so deregulation in London could lead to a fall in the number of slight casualties involving buses.Although there were fears that changes in the management of bus operations or financial pressures might lead to increased accident rates following deregulation, there no evidence in the findings to support such fears.This paper was first presented at the 3rd International Conference on Competition and Ownership in Surface Public Transport at Mississauga, Canada on 25–29 September 1993. The author is grateful to the Department of Transport for the speed and efficiency with which they provided special tabulations from the road accident database for this study.     

Flexible substitution patterns in models of mode and time of day choice: new evidence from the UK and the Netherlands

Modelling the temporal response of travellers to transport policy interventions has rapidly emerged as a major issue in many practical transport planning studies and is recognised to hold particular challenges. The importance of congestion and its variation over the day, together with the emergence of time-dependent road user charging as a policy tool, emphasise the need to understand whether and how travellers will change the timing of their journeys. For practical planning studies, analysts face a major issue of relating temporal changes to other behavioural changes that are likely to result from policy or exogenous changes. In particular, the relative sensitivity of time and mode switching has been difficult to resolve. This paper describes a study undertaken to determine the relative sensitivity of mode and time of day choice to changes in travel times and costs and to investigate whether evidence exists of varying magnitudes of unobservable influences in time of day switching. The study draws on data from three related stated preference studies undertaken over the past decade in the United Kingdom and the Netherlands and uses error components logit models to investigate the patterns of substitution between mode and time of day alternatives. It is concluded that the magnitude of unobserved influences on time switching depends significantly on the magnitudes of the time switches considered. With time periods of the magnitude generally represented in practical modelling, i.e. peak periods of 2–3 hours, time switching is generally more sensitive in these data than mode switching. However, the context of the modelling and the extent to which relevant variables can be measured will strongly influence these results.     

A continuum model for the dispersion of traffic on two-lane roads

A continuum model for two-lane traffic flow is developed using the theory of kinematic waves in which the wavespeeds in the two lanes are assumed constant but unequal. The transient behaviour is found exactly using Riemann's method of characteristics and an asymptotic model of the long time flow is described. It is shown, that for large times, the traffic concentration moves with a weighted mean wavespeed of the two lanes and disperses about this mean speed as a result of interlane concentration differences generated by the relative wavespeeds. The dispersion can be described by a virtual coefficient of diffusion proportional to the square of the differences of the two wavespeeds and inversely proportional to the rate of lane changing. The technique is extended to describe three-lane traffic flow and to include the dependence of wavespeed upon concentration.     

Exploring the effects of passenger rail franchising in Britain: Evidence from the first two rounds of franchising (1997-2008)

This paper provides an up-to-date review of the previous literature concerning the impact of passenger rail franchising on productivity and costs in Britain, and also presents important new evidence. In particular, the extension in time of previously-used datasets offers the first opportunity to study the impacts of re-franchising. The previous literature emphasised the failure of franchising to produce sustained productivity gains, with a sharp deterioration in productivity after 2000. The new evidence presented offers a somewhat more positive view of the British experience. It suggests that part of what was previously considered to be falling productivity may in fact be due to exogenous changes in diesel prices. Further, new data suggests that the recent increases in costs have resulted in higher quality of service. Finally, competitive re-franchising, and the associated unwinding of short-term management and re-negotiated contracts, seems to have led to improvements in productivity between 2006 and 2008. Nevertheless, it remains the case that passenger rail franchising in Britain has failed to reduce costs in the way experienced in many other industries and in rail in other European countries. The evidence is that somewhat larger franchises, avoiding overlapping and optimising train density and length, should reduce costs. We also speculate that the major increase in wages and conditions of staff might be moderated by longer franchises, although that remains to be proved. This re-appraisal of the British case is important in the context of the wider international interest in the use of franchising in passenger rail, and its relevance to the current review of ways of introducing competition into the domestic rail passenger market in Europe.     

The 2008 New Zealand public transport management act: Rationale, key provisions, and parallels with the United Kingdom

In January 2009, following a lengthy industry review and consultation process, the New Zealand Public Transport Management Act (PTMA) came into force. The Act allows Regional Transport Authorities, as the primary procurers of public transport services, to place either a control or a contracting requirement upon services that are registered as commercial requiring no subsidy. The imposition of either the control or the contracting requirement is designed to facilitate greater system integration, improve service continuity and enhance services to the customer, andallow the Authority to invest in key strategic projects, such as integrated fares and ticketing, so as to grow patronage.The PTMA’s other objective is to ensure improved value for public subsidies. Recent years have seen significant subsidy inflation for seemingly little commensurate benefits. The Act will allow the Regional Transport Authority to achieve greater value for money through improved farebox, a shift to longer, larger contracts to increase competition in the market, a more appropriate allocation of risk, and the removal of the ability of operators to ‘game’ the current system by using strategically placed commercial services as barriers to competition.Similar concerns have also stimulated new legislation in the UK and this paper illustrates the parallels in the environment and proposed response.     

混合动力是唯一的选择吗?--高燃油税对欧洲动力技术发展的影响

“欧洲人已经学会了如何面对昂贵的燃油价格 (主要是指燃油税)。数十年来,欧洲社会一直努力去适应较高的燃油价格,而且已经建立了许多有效的机制     

Forecasting road traffic conditions using a context-based random forest algorithm

With the ability to accurately forecast road traffic conditions several hours, days and even months ahead of time, both travellers and network managers can take pro-active measures to minimise congestion, saving time, money and emissions. This study evaluates a previously developed random forest algorithm, RoadCast, which was designed to achieve this task. RoadCast incorporates contexts using machine learning to forecast more accurately contexts such as public holidays, sporting events and school term dates. This paper evaluates the potential of RoadCast as a traffic forecasting algorithm for use in Intelligent Transport System applications. Tests are undertaken using a number of different forecast horizons and varying amounts of training data, and an implementation procedure is recommended.