TØI Vitenarkiv
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Improving walking conditions for older adults. A three-step method investigation
Get PDFThe benefits of walking are widely recognized. In this regard, the Norwegian government has urged local authorities to develop walking strategies. The aim of such strategies is to influence a local walking culture and framework conditions for pedestrians. Older citizens are an important focus group because what is an accessible environment for them can be attractive for all groups. The primary aim of this study is to improve our understanding of how physical, social and individual factors affect whether older groups perceive that they need, can and want to walk. Second, we show how a mixed-method approach for collecting data gives an important input when planning a walking strategy. Combining quantitative and qualitative data gave deeper insights into how elders perceived their walking environment. The three steps (survey, participatory observation and workshop) made it possible to involve elders and practitioners from the municipality and the Norwegian Public Roads Administration directly in the study. This gave first-hand experience about how to facilitate the environment for older pedestrians. The findings suggest that the need, can and want dimensions of walking interact and reinforce each other. We find that measures affecting more than one such dimension seem to provide the best response for walking activity. This can be important for practitioners to take into consideration when developing good walking areas in the city.acceptedVersio
Traffic forecasting at ‘strategic’, ‘tactical’ and ‘operational’ level: A differentiated methodology is necessary
Get PDFIn this paper we discuss why traffic forecasting is such a difficult endeavour, and point at alternatives to the current widespread use of traffic models almost independently of the problem faced by the planners. It will be argued that it is inherently impossible to make exact predictions about the magnitude of ‘general’ traffic growth 20–30 years ahead, since many of the influencing factors depend on inherently unpredictable geopolitical trajectories as well as contested political decision-making. Due to the context-dependency of each particular planning situation, it is also hardly possible to make exact, quantitative predictions about the impact of implementing a specific infrastructure project, compared to ‘doing nothing’. We propose separating the so-called strategic, tactical and operational levels of traffic forecasting into three distinct methodological approaches reflecting the different degrees of openness and closure of the systems at hand: scenario analyses at the strategic level; theory-informed, mainly qualitative analyses supplemented with simple calculations at the tactical level; while more traditional micro-simulations should be applied only at a detailed operational level.acceptedVersio
Optimal profits under environmental regulation: the benefits from emission intensity averaging
Get PDFIn this paper we analyze the economic effects of implementing EPA’s newly proposed regulations for carbon dioxide (CO2) on existing U.S. coal-fired power plants using nonparametric methods on a sample of 144 electricity generating units. Moreover, we develop an approach for evaluating the economic gains from averaging emission intensities among the utilities’ generating units, compared to implementing unit-specific performance standards. Our results show that the implementation of flexible standards leads to up to 2.7 billion dollars larger profits compared to the uniform standards. Moreover, we find that by adopting best practices, current profits can be maintained even if an intensity standard of 0.88 tons of CO2 per MWh is implemented. However, our results also indicate a trade-off between environmental and profit gains, since aggregate CO2 emissions are higher with emission intensity averaging than with uniform standards.submittedVersio
A case study of parking charges at work places – effects on travel behaviour and acceptance
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A statistical law in the perception of risks and physical quantities in traffic
Get PDFThis paper suggests that a universal psychophysical law influences the perception of risks and physical quantities in traffic. This law states that there will be a tendency to overestimate low probabilities or small quantities, while high probabilities or large quantities may be underestimated. Studies of the perception of risk and physical quantities in traffic have found a highly consistent pattern, which shows that:
1.
Pedestrians intending to cross the road overestimate the stopping distance of cars travelling at low speed and underestimate the stopping distance of cars travelling at high speed.
2.
Car drivers intending to overtake overestimate the distance needed at low speed, but underestimate it at high speed.
3.
Car drivers asked to accelerate from standstill to a given speed overshoot the target speed; when asked to slow down to a stated speed, drivers also overshoot the target speed.
4.
When asked what speed to choose to save a given amount of time on a trip of given length, drivers overestimate target speed when initial speed is low and underestimate it when initial speed is high.
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Drivers overestimate the increase in risk associated with a small increase in speed and underestimate the increase in risk associated with a larger increase in speed.
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Drivers overestimate the risk of apprehension for traffic offences when it is low and underestimate it when it is high.
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Road users overestimate the risk associated with comparatively safe modes of transport and underestimate the risk associated with comparatively hazardous modes of transport.
The paper gives examples of all these misperceptions of physical quantities and risk.submittedVersio
Some implications of an event-based definition of exposure to the risk of road accident
Get PDFThis paper proposes a new definition of exposure to the risk of road accident as any event, limited in space and time, representing a potential for an accident to occur by bringing road users close to each other in time or space of by requiring a road user to take action to avoid leaving the roadway. A typology of events representing a potential for an accident is proposed. Each event can be interpreted as a trial as defined in probability theory. Risk is the proportion of events that result in an accident. Defining exposure as events demanding the attention of road users implies that road users will learn from repeated exposure to these events, which in turn implies that there will normally be a negative relationship between exposure and risk. Four hypotheses regarding the relationship between exposure and risk are proposed. Preliminary tests support these hypotheses. Advantages and disadvantages of defining exposure as specific events are discussed. It is argued that developments in vehicle technology are likely to make events both observable and countable, thus ensuring that exposure is an operational concept.acceptedVersio
Can electronic stability control replace studded tyres?
Get PDFBased on recent studies, this paper examines whether an increased use of electronic stability control can replace studded tyres. A re-analysis of a study that evaluated the effects on accidents of changes in the use of studded tyres in major cities in Norway is presented. It is found that if all cars have electronic stability control, the use of studded tyres can be reduced to about 15 percent before any increase in the number of accidents occurs. Even if studded tyres were eliminated entirely, any increase in the number of accidents is likely to be considerably smaller than it would have been if electronic stability control had never been invented.submittedVersio
Axioms of a Polluting Technology: A Materials Balance Approach
Get PDFThis paper aims to present an economic model characterized by a set of axioms that are consistent with the laws of thermodynamics. Two new axioms—weak G-disposability (i.e., weak directional disposability) and output essentiality—are introduced to satisfy the materials balance principle and the entropy law, respectively. The axiomatic production model is compared to other well-known production models that account for the joint production of good and bad outputs to illustrate the advantages of the new modeling approach.acceptedVersio
Green urban distribution : evaluation of adapted measures for the city of Oslo
Get PDFThe paper presents results from a study of urban freight measures in the city of Oslo. More specifically, it presents methods and results from an ex ante study of seven potential city logistics measures. The study is based on a survey among 67 representatives from three stakeholder groups. Furthermore, a generic ex post evaluation framework is presented, and an example of how the framework has been applied to evaluate a demonstration of electric distribution vehicles. The study gives explicit and systematic documentation of multiple stakeholder perceptions related to several measures in urban freight. Only a few studies have done so previously. The measure assessed most positively is environmentally friendly vehicles. The ex post evaluation of demonstrated electric vehicles suggests that electric vans can serve parts of the express shipment market very well with their existing range. Removing uncertainties related to their performance and financial viability is an important task for further take-up of these vehicles. The study provides a basis for designing viable and effective measures in order to achieve more environmentally-friendly and effective freight distribution in the city center of Oslo. Also important is the methodology providing a systematic and informed approach to policy design and implementation. As such, the study is useful to other cities and scientists in search for viable and efficient measures in specific local contexts. Green Urban Distribution: Evaluation of adapted measures for the city of Oslo. Available from: https://www.researchgate.net/publication/275889293_Green_Urban_Distribution_Evaluation_of_adapted_measures_for_the_city_of_Oslo [accessed Jan 18, 2016].Green urban distribution : evaluation of adapted measures for the city of OslosubmittedVersio
Methodological guidelines for developing accident modification functions
Get PDFThis paper proposes methodological guidelines for developing accident modification functions. An accident modification function is a mathematical function describing systematic variation in the effects of road safety measures. The paper describes ten guidelines. An example is given of how to use the guidelines. The importance of exploratory analysis and an iterative approach in developing accident modification functions is stressed. The example shows that strict compliance with all the guidelines may be difficult, but represents a level of stringency that should be strived for. Currently the main limitations in developing accident modification functions are the small number of good evaluation studies and the often huge variation in estimates of effect. It is therefore still not possible to develop accident modification functions for very many road safety measures.submittedVersio