| 1. |
- Engelson, Leonid
(författare)
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On dynamics of traffic queues in a road network with route choice based on real time traffic information
- 2003
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Ingår i: Transportation Research Part C. - : Elsevier BV. - 0968-090X .- 1879-2359. ; 11:2, s. 161-183
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Tidskriftsartikel (refereegranskat)abstract
- Introducing real time traffic information into transportation network makes it necessary to consider development of queues and traffic flows as a dynamic process. This paper initiates a theoretical study of conditions under which this process is stable. A model is presented that describes within-one-day development of queues when drivers affected by real-time traffic information choose their paths en route. The model is reduced to a system of differential equations with delay. Equilibrium points of the system correspond to constant queue lengths. Stability of the system is investigated using characteristic values of the linearised minimal face flow. A traffic network example illustrating the method is provided.
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| 2. |
- Vythoulkas, P. C., et al.
(författare)
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Modeling discrete choice behavior using concepts from fuzzy set theory, approximate reasoning and neural networks
- 2003
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Ingår i: Transportation Research Part C. - 0968-090X .- 1879-2359. ; 11:1, s. 51-73
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Tidskriftsartikel (refereegranskat)abstract
- Models of discrete choice analysis are usually based on the random utility framework. They assume that decision makers make decisions that maximize their utility. Alternative formulations of the problem have also been proposed in the literature. These approaches model the decision makers' perceptions of the attributes of the various alternatives using fuzzy sets and linguistic variables, and the decision process itself, using concepts from approximate reasoning and fuzzy control. The underlying assumption is that decision makers use a few simple rules that relate their vague perceptions of the various attributes to their preferences towards the available alternatives. The paper extends this approach by incorporating rule weights, which capture the importance of a particular rule in the decision process. It also presents an approach for calibrating the weights using concepts from neural networks. A case study, involving mode choice, is used to demonstrate the potential of the approach and compare it to alternative formulations and methodologies.
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| 3. |
- Varhelyi, Andras, et al.
(författare)
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The effects of in-car speed limiters – Field studies
- 2001
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Ingår i: Transportation Research Part C: Emerging Technologies. - 0968-090X. ; , s. 191-211
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Tidskriftsartikel (refereegranskat)abstract
- Field trials in three European countries, the Netherlands, Spain and Sweden were carried out in order to investigate the effects of an in-car speed limiter. The trials were carried out on urban and rural roads including motorways. A so-called unobtrusive instrumented car was used, where all the measuring equipment was hidden. All the speed limit categories in the respective countries, ranging from 30 km/h to 120 km/h were included. The results showed that the effects of the limiter were greatest in free driving conditions outside platoons. How-ever, the limiter also had effects in congested traffic. Momentary high speeds were suppressed effectively, which resulted in less variation of speeds. Approach speeds at roundabouts, inter-sections and curves became smoother, car-following behaviour became safer in the speed range of 30 km/h to 50 km/h. On the other hand, in the speed range of 70 km/h to 90 km/h a slightly higher number of short time-gaps suggested less safe car-following behaviour. Other negative behavioural effects were slightly increased travel time and the increased frustration and stress for the drivers caused by the limiter. The majority of the subjects accepted the speed limiter as a driver-operated system. Half of the drivers would accept the limiter volun-tarily in their cars.
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