Journal: Working Paper / IVT

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Institut für Verkehrsplanung und Transportsysteme (IVT), ETH Zürich

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2006 - 20089
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Publications 1 - 9 of 9
  • A high-performance traffic flow microsimulation for large problems
    Item type: Working Paper
    Charypar, David; Balmer, Michael; Axhausen, Kay W. (2008)
    Working Paper / IVT
    Traffic flow microsimulations are interesting for transport planning problems due to their high temporal and spatial resolution. Unfortunately, most of them involve high computational costs making them impractical for running large scale scenarios. In this paper, we present how we extend our previous event-driven queue-based mircosimulation to run efficiently on parallel computers. Using appropriate load balancing and minimizing communication interfaces, we are able to simulate a test scenario involving 7 million simulated person days on a road network with 28k links in 87 seconds on 64 CPUs. Furthermore, we add support for signaled intersections that makes the model well suited for application to urban street networks. Finally, we show that our resulting model reproduces a reasonable relation between traffic flow and density similar to fundamental diagrams extracted from real world counts data.
  • Long-term and mid-term mobility decisions during the life course
    Item type: Working Paper
    Beige, Sigrun; Axhausen, Kay W. (2007)
    Working Paper / IVT
    Long-term and mid-term mobility of people involves on the one hand decisions about their residential locations and the corresponding moves. At the same time, the places of education and employment play an important role. On the other hand the ownership of mobility tools, such as cars and different public transport season tickets, are complementary elements in this process, which also bind substantial resources. These two aspects of mobility behavior are closely connected to one another. A longitudinal perspective on these relationships is available from people’s life courses, which link different dimensions of life together. In order to study the dynamics of long-term and mid-term mobility decisions, a longitudinal survey covering the 20 year period from 1985 to 2004 was carried out at the beginning of 2005 in a stratified sample of municipalities in the Zurich region, Switzerland. The paper shows that there exists a strong interrelation between the two aspects of long-term and mid-term mobility. The residential mobility is influenced by the ownership of the different mobility tools and vice versa. Thereby the mobility tool ownership remains comparably stable over longer periods of time.
  • Weekly rhythm in joint time expenditure to all at-home and out-of-home activities
    Item type: Working Paper
    Nurul Habib, Khander M.; Miller, Eric J.; Axhausen, Kay W. (2007)
    Working Paper / IVT
    This paper uses the Kuhn-Tucker demand system modeling technique to investigate the capacity of a typical week in capturing rhythms in activity-travel behavior. It considers all possible activity types within a weeklong modeling time frame. Complex interactions in time expenditure between at-home versus out-of-home activities and among different out-of-home activities are captured by introducing behavioral elements in the model in terms of baseline preference, time translation, and satiation effects. The Kuhn-Tucker demand system model used in this paper is a random utility maximization model with the inherent assumption that every individual maximizes his/her total utility in allocating time to the activities under consideration within the modeling time frame. Models are developed for each individual week of a six-week travel diary, the MobiDrive dataset for Karlsruhe and Halle, Germany. Each model contains 83 variables and reveals behavioral details of our complex activity-travel behavior. Based on the performances of the models in terms of fitting observed data and parameter values of specific variables, it is clear that typical week modeling time fame is capable of capturing rhythms of our activity-travel behavior sufficiently. The paper concludes with the recommendation that the availability of activity diary data for a multiweek time period would further enhance our understanding on this issue.
  • Vulnerability Assessment of the Swiss Road Network
    Item type: Working Paper
    Erath, Alex; Birdsall, John; Axhausen, Kay W.; et al. (2008)
    Working Paper / IVT
    This paper presents a methodology for integrating vulnerability due to natural hazard into current infrastructure management systems. It is mainly concerned with presenting a methodology to assess link failure induced transportation related consequences including congestion related effects across a national network. The main challenge hereby considered is how to overcome the calculation time intensity of this equilibrium-based via equilibrium. Rather than employing the complete network for analyising a link failure, subnetworks are employed to model the spatially restricted demand shifts effects around a failed link. Each subnetwork is formulated by cutting a geographically defined selct of links and nodes out of the national network and including the internal and external demand transversing the subnetwork boudary. The failure consequences, even for links with long path distances or long detours, assessed with the subnetwork are very consistent with those considering the full network. A statistical model, highlighting and detailing the key factors defining transport related consequences, is developed from the computed link failure consequences and link parameters. Lastly, the findings highlight the potential gains to be derived from directly including rail networks and covering the potential mode shifts in the assessment.
  • Travel behavior changes of commuters from 1970-2000
    Item type: Working Paper
    Froehlich, Philipp (2007)
    Working Paper / IVT
    The paper describes research on estimating sequential discrete choice models for mode choice, destination choice and interzonal trip generation of commuters from 1970 to 2000 in Switzerland. The research is based on detailed data sets that track the development of the private and public transport system and the socioeconomic variables on the level of local municipalities. Major changes in mode choice were identified via the estimated parameters of travel cost, quantity adjusted car ownership cost and car ownership per licensed driver. The results of the interzonal trip generation show that demand reacts with positive elasticity to accessibility, but also that the accessibility of a zone becomes less important for the generation of interzonal work trips over time.
  • Location choice modeling for shopping and leisure activities with MATSim
    Item type: Working Paper
    Horni, Andreas; Scott, Darren M.; Balmer, Michael; et al. (2008)
    Working Paper / IVT
    This paper presents the concept, implementation and empirical testing of the MATSim (Multi Agent Transport Simulation Toolkit) location choice module for shopping and leisure activities. MATSim is designed to handle large-scale scenarios. Thus, computational efficiency, that is fast convergence, while maintaining behavioral precision is a fundamental objective. We show that to achieve this goal Hägerstrand’s time-geographic approach can be incorporated easily and consistently into MATSim and into disaggregated location choice simulations in general. Our novel time-geographic algorithm, tailored for the use in MATSim, is derived from a po tential path area algorithm. Furthermore, it is extended to handle chains of multiple shop or leisure activities between two anchored activities (i.e., those with fixed start times, durations and locations) by using recursion. To improve both the behavioral precision and the stability of our model, we show how time-dependent capacity restraints can be incorporated explicitly into iterative disaggregated location choice simulations as capacity restraints for activity locations have an effect on peo ple’s location choices, similar to the effect of road capacity restraints on people’s route choices. To our knowledge, to date, only static activity location attributes, such as opening hours and location size, are incorporated explicitly in disaggregated location choice simulations and thus our contribution is also meant to open up a discussion. Finally, simulation results for a large-scale scenario for the Zürich region of Switzerland, using more than 60,000 people and 7,800 shop or leisure activity locations, show that our model is computationally feasible and behaviorally sound.
  • Mapping social networks in time and space
    Item type: Working Paper
    Ohnmacht, Timo (2006)
    Working Paper / IVT
    Over the last few decades, the motives and determinants of individual travel behaviour have been analysed from different perspectives. Whereas the main approach explains personal mobility due to the travellers' sociodemographics and the generalised costs of travel, travel behaviour research has added several more complex analysis directions such as role patterns, household interactions, time budgets, activity planning, life styles, etc. This working paper addresses a further possible determinant to help us understand travel behaviour, this being the size and structure of social networks. Recognising the ongoing pluralisation and differentiation within society, it seems crucial to investigate social realities to understand traveller behaviour in greater detail. This study develops a concept, which allows us to explore the relationship between social networks and (leisure) travel. Several mappings of interviewees ́ network geographies will be combined with their related transcribed mobility biography interviews, to explain different cases of mobility patterns.
  • Dominance variables and intervening opportunities for choice set generation
    Item type: Working Paper
    Cascetta, Ennio; Pagliara, Francesca; Axhausen, Kay W. (2007)
    Working Paper / IVT
    Models adopted in the literature to represent spatial choices are generally rather elementary and result in the application of random utility theory to the choice among hundreds of alternatives. The attributes are usually related to spatial attractiveness and to generalised travel cost without any reference to perception/availability attributes.The objective of this paper is twofold: to use perception/availability variables named dominance variables for modelling spatial choices to have a better predictive model and to use dominance criteria as weights for the sampling probabilities to show how weighted sampling of alternatives provide parameters estimates “closer” to the full choice set.
  • Transport infrastructure and spatial development in Switzerland between 1950 and 2000
    Item type: Working Paper
    Tschopp, Martin; Axhausen, Kay W. (2006)
    Working Paper / IVT
    This paper focuses on the impact of transport infrastructure on the population change of municipalities and regions. Accessibility is both the primary service provided by transport infrastructure and the link between transport infrastructure and land use. It can be a measure of the spatial impact of newly-built transport infrastructure and it can enhance the attractiveness of a region’s location. A suitable approach for measuring the spatial impact of accessibility is the quantitative method of growth modeling, which accounts for spatial correlation by using OLS models, OLS models corrected for spatial correlations, and multilevel growth models. Multilevel growth models combine an individual level, which represents disaggregate behavior, with a contextual macro level. The following questions were investigated: Where did accessibility change occur, when and how did these changes take place, and to what extent did accessibility change influence spatial development? First results indicate that the influence of accessibility on spatial development differs considerably over time and space: its strength declines the more developed a region becomes and the closer it approaches the present.
Publications 1 - 9 of 9