44 research outputs found

    Traveller Behaviour: Decision making in an unpredictable world

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    This paper discusses the nature and consequences of uncertainty in transport systems. Drawing on work from a number of fields, it addresses travellers’ abilities to predict variable phenomena, their perception of uncertainty, their attitude to risk and the various strategies they might adopt in response to uncertainty. It is argued that despite the increased interest in the representation of uncertainty in transport systems, most models treat uncertainty as a purely statistical issue and ignore the psychological aspects of response to uncertainty. The principle theories and models currently used to predict travellers’ response to uncertainty are presented and number of alternative modelling approaches are outlined. It is argued that the current generation of predictive models do not provide an adequate basis for forecasting response to changes in the degree of uncertainty or for predicting the likely effect of providing additional information. A number of alternative modelling approaches are identified to deal with travellers’ acquisition of information, the definition of their choice set and their choice between the available options. The use of heuristic approaches is recommended as an alternative to more conventional probabilistic methods

    Measuring Impacts of New Highways Capacity – A Discussion of Potential Survey Methods

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    The paper reviews survey methods that might be used to detect the various impacts of new highway capacity (changes in flow and network travel times; behavioural responses such as rerouting, change in departure times, change of mode, redistribution and change in trip frequency; and changes in land use). The review was conducted in the context of a study for TRRL which sought to establish the feasibility of measuring responses to new highway capacity. The paper considers, in turn, surveys of traffic flow, public transport usage and network travel times, methods of estimating origin-destination matrices and a variety of questionnaire and interview techniques which might be used to collect individual travel data (roadside interviews; stopline surveys; household interviews; trip-end interviews; self completion questionnaires; retrospective, prospective and stated preference questions; panel surveys and indepth interviews). There is also a brief discussion of methods to determine bight movements and land use effects. The paper should not be regarded as a source of detailed information about the various types of survey but rather as a review of their comparative strengths and weaknesses in the given context

    On the use of Fixed Trip Matrices for the Evaluation of Urban Highway Schemes

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    This paper begins with a summary of the theoretical background to the question of fixed or variable trip matrices and briefly reviews current UK advice and practice. The main bulk of the paper is a review of published evidence as to whether network improvements do or do not affect trip matrices. The conclusion is that there is strong evidence of local land use changes, particularly adjacent to major new intersections or access points. However, it is clear that any new development is dependent on the existence of a capacity for relocation or growth in the local economy and a not unfavourable stance by the local planning authority. In the absence of new land development, however, there is little published evidence of changes in trip matrices following network improvements. The conclusion drawn from this evidence, from public interest in the question of generated traffic, and from the lack of reliable forecasting models, is that sensitivity analyses should be carried out to determine the possible effects of changes in the trip matrix before any decision is taken to ignore them

    A Review of Drivers' Requirements for Guidance and Information in CLEOPATRA Cities.

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    The contents of this working paper were submitted in modified format as the End Users’ Requirements section of Deliverable 1, Work Package 3, of the European Commission DG X111 C Telematics for Transport project CLEOPATRA (City Laboratories Enabling Organisation of Particularly Advanced Telematics Research and Assessment), project no. TR 1012, June 1996. Various studies on drivers' requirements for guidance and information have been carried out in both Europe and the USA. An executive summary of these requirements is provided in the following sub-section. The full details of research previously conducted is given in section 2, where the main findings from a selection of studies are summarised. The subsequent section 3 on Drivers’ Requirements in CLEOPATRA Cities, gives city specific requirements where previous work has been undertaken to assess these as part of work for other European projects. Finally the conclusions on Drivers’ Requirements are summarised in section 4 and research references listed in section 5

    Urban road user charging and workplace parking levies

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    In this chapter we will briefly describe the provision made for the introduction of road user charging and workplace parking levies in the Transport Act 2000 and equivalent legislation for London and Scotland. After reviewing the background to these provisions, we will discuss the practical issues and policy questions which arise for any local authority wishing to take advantage of their new powers. Our discussion will draw attention to developments that have occurred since the passing of the Act and conclude on the prospects for charging schemes in the UK

    Estimating the impact of time-based road user charges on risk taking by drivers.

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    This study, conducted for ethical reasons on a driving simulator, has indicated that drivers take more risks when they are being charged for their use of roadspace on the basis of time, than they do when they are not subject to such charges. This effect is highly significant for some measures of risk taking (e.g. red light violation and illegal overtaking) but less so for others. The effect is apparent even at very low charge levels and is observed irrespective of whether the charge is based on total travel time or time spent below specified speeds (‘congestion charges’). There are however some differences in the types of risky behaviour engendered by these two charging regimes. These results have obvious and serious implications for the implementation of time-based road user charges

    Microsimulation of Organised Car Sharing – Model Predications and Policy Implications.

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    This paper presents the results of a range of tests of organised car sharing schemes. The performance of the schemes is predicted using a sophisticated microsimulation model. A brief resume of the model is followed by a description of the tests and an analysis of their results. Conclusions are drawn on the place of organised car sharing within broader transport policies, the performance of the model when compared to the available empirical data and directions for public research. The tests here presented include: a series of sensitivity analyses; tests of organisational strategies for car sharing schemes; tests of schemes in a variety of locations and at a variety of scales and finally a batch of tests which investigate the effect of major changes in the operating environment of car sharing schemes - changes in the price of fuel and public transport fares and the provision of parking space incentives for car sharers for example

    Drivers’ Response to In-Vehicle Route Guidance Information Systems: An Experiemnt with a Mock-Up Guidance System.

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    The paper reports an exploratory study, using an unusual technique to investigate drivers' response to in-vehicle route guidance information systems. Eighteen drivers were recruited, and asked to make a series of three trips in an unfamiliar area. Each driver was given turning advice, via a speech synthesiser, on one of these trips. This advice was based on average traffic conditions for the time of day. Unbeknown to the drivers, the advice was in fact triggered by the experimenter, who was riding as a back-seat passenger. Details were kept of times and routes taken with and without guidance, and with different levels of network familiarity. Records were also kept (using questionnaires and video and audio recording) of planning and route-following strategies. As expected, both receipt of guidance and even very rudimentary network familiarity resulted in reduced journey times, and routes closer to the guidance recommendations. The study indicated that factors including the directness of possible routes, their perceived complexity, and familiarity all affect route choice, but to different extents for different individuals and under different circumstances. Error was shown to be important in determining the route actually followed when guidance was withheld. The study showed that giving in-vehicle guidance using the mock-up technique described is practicable, and does influence drivers' route-choice and route-following behaviour. A possible future study is outlined, aimed at identifying the determinants of the drivers' level of compliance with advice when they believe that advice is based on real-time traffic information

    The Simulation of Organised Car Sharing (2) – The Simulation Models and their Calibration.

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    This paper is one of a series describing the methods and findings of a TRRL sponsored project to simulate organised car sharing. This volume describes the simulation model and its calibration. The model requires as input a description of each individual tripmaker within the system (there are 180,000 such individuals in the study area under investigation). Using these individuals as actors, the model simulates, within a calibrated choice model, the decision-of each of them in turn whether or not to apply to join a hypothesised car sharing scheme. The matching of such applicants to form potential car pools is then effected in a special routine. A second calibrated choice model then simulates the decisions by each of the applicants whether to enter an arrangement with any of the potential partners with whom they have been provisionally matched. A mutual evaluation of utilities then determines which arrangements will actually come to fruition. The microsimulation approach to transport modelling involves consideration of choice options by the fundamental actors within the system - the individual tripmakers. The approach is inherently attractive but only recently have decreasing computer costs made microsimulation a viable branch of travel demand modelling. The choice models were calibrated on the basis of a series of field surveys which were designed to mirror exactly the simulation models - respondents were invited to make decisions and to evaluate proposals drawn from the simulation models themselves. Thus the respondents effectively became actors within the simulation and their reactions to the choices available to them were used to calibrate the models. Previous investigations of car sharing have concentrated either on the behavioural and psychological aspects of the mode with little attempt to estimate the global consequences of these or have concentrated on the probable demand for the mode with little attempt to consider the interaction between potential matchees . The microsimulation approach adopted here has successfully combined a calibrated model of demand for the mode with an accurate rendition of the supply side - the matching of individual trip makers with compatible requirements and, finally, a calibrated model of the decision whether or not to enter an arrangement with a specified individual. This approach has been particularly appropriate to the modelling of organised car sharing but can obviously provide the basis for a whole range of behaviourally orientated planning models

    Some Thoughts on the Ways in Which Drivers Choose & Store New Information About Routes & How new Information Might be Processed By Them

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    This note represents a mind dump of my thoughts on this topic as at mid April 1992, it does not purport to be a finished paper and leaves several issues unanswered. I was stimulated to put my thoughts on paper after reading the first draft of Nicholas Gotts' digest of his DPhil Thesis (Gotts, 1992). I was particularly keen to set down my thoughts on strategic planning and tactical adjustment as elements of the route choice process and to hrther develop the theme of different forms of mental maps since this is a topic in which I first dabbled within my own, undergraduate, dissertation. The theme of the note was intended to be: what implications does the way in which a driver stores information about the road system have for the design, content impact of route guidance and information systems? - but, as is often the case with mind dumps, the original theme spawned a variety of sub issues
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