Journal: Arbeitsberichte Verkehrs- und Raumplanung

Abbreviation

Publisher

FCL, Singapore ETH Centre

Journal Volumes

ISSN

Description

Filters

2012 - 20206
Reset filters

Search Results

Publications 1 - 6 of 6
  • Simulating urban transport for a week time horizon
    Item type: Working Paper
    Ordonez Medina, Sergio Arturo; Erath, Alexander; Axhausen, Kay W. (2012)
    Arbeitsberichte Verkehrs- und Raumplanung
    MATSim is a large-scale multi-agent, activity-based transport simulation model. It can simulate each person in a urban area, managing millions of agents in reasonable computation times. Besides supply information, MATSim needs a planned activity schedule for every person as input data. Its time horizon is one day, and the activity-trip chains have to be fully defined before each simulation (start-time, duration, location, trip mode, and sequence for the entire day). MATSim scores the simulation, mutates agents' plans and executes a new simulation many times, optimizing the macroscopic indicators and reaching user equilibrium conditions. However, the one day time horizon is a hard restriction for studying current transport planning challenges using MATSim. Recent studies show that the behavioral variety of travelers can not be well analyzed with only one day simulation results. Usual analysis procedures, like clustering the population according to their travel behavior, need multi-day information to account for intra-personal variability. Furthermore, longer time horizons allow to include restrictions like time and money budgets, and to simulate individual mode choice over time, identifying mode clienteles. Developments of advanced time consumption travel models require observations of at least a week for calibration purposes, because a complete cycle of work and leisure must be included. In conclusion, time consumption decisions that humans take inside a day depend on individual and collective behaviors. These behaviors only can be simulated and analyzed with longer term models. Understanding the importance and pertinence of simulating transport with a multi-day time horizon, this paper discusses how MATSim can be expanded to execute one week time activity plans. The discussion is conceptual because no full implementation has been developed yet. The paper emphasizes two key aspects of the expansion: optimization strategies, and the generation of weekly plans. For each aspect alternatives are proposed, analyzed and compared. The impact of the proposed development on each step of the simulation process is taken into account. The problem of scheduling and re-scheduling and its relation to computational time in large-scale scenarios has to be kept in mind for weekly plans even more so than for daily plans. Activity plan generation procedures ranging from simpler, but faster methods to advanced ones, involving econometric approaches or complex mental processes, are compared. Concepts like fixed and floating activities, activity agendas or shared activities (within households or with social networks) have to be evaluated for their impact. Furthermore, several options for performing the optimization of plans are presented, highlighting their advantages and disadvantages (e.g. full-week re-planning or end-of-day re-planning). Computing time and memory consumption are taken into account according to previous measures and expected indicators. It is easy to realize that the mobility simulation (traffic flow) module does not need significant changes when the total time is modified. However, if a within-week re-planning strategy is implemented modifications in this module and its implications are explained and evaluated as well. The paper concludes with a proposed methodology for developing this MATSim extension
  • Quantifying bicycling stress level using virtual reality and electrodermal activity sensor
    Item type: Working Paper
    Nazemi, Mohsen; van Eggermond, Michael A.B. (2020)
    Arbeitsberichte Verkehrs- und Raumplanung
    The application of wearable wireless electrodermal activity (EDA) devices in virtual reality (VR) experiments has become increasingly popular and lends itself for the application in behavioral research for transport planning. The type of infrastructure and interaction with other road users can invoke different arousal levels in urban bicyclists, which can be modeled with VR applications and captured by EDA sensors. At the intersection of engineering, psychology, and physiology, this research attempted to quantify bicycling stress levels using a bicycle simulator combined with immersive 360-degree virtual reality and an EDA sensor. Overall, 150 participants rode through 5 different bicycling environments in VR while their elicited skin conductance responses (SCRs) were passively collected by an EDA sensor that was connected to the participants for the duration of the experiment. Analysis of the signal for the entire stretch of the bicycling course did not yield significant differences in SCRs between different bicycling environments. However, comparing smaller segments of the bicycling course revealed significant differences. Bicycling on the side- walk shared with pedestrians caused higher stress levels while bicycling on the segregated bicycle path found to be the least stressful. Evidence was found of a link between self-reported perceptions of safety and SCR rates. The results of this research shows a promising path in using VR experiments to identify stressful events and locations and to quantify bicycling stress level for non-existent future facility designs.
  • Studying cyclists’ behavior in a non-naturalistic experiment utilizing cycling simulator with immersive virtual reality
    Item type: Working Paper
    Nazemi, Mohsen; van Eggermond, Michael A.B.; Erath, Alexander; et al. (2018)
    Arbeitsberichte Verkehrs- und Raumplanung
    This study investigates the combination immersive virtual reality (VR) and an instrumented cycling simulator for in-depth behavioral studies of cyclists. To this end, a cycling simulator was developed, virtual environments resembling Singapore were created, combined with the output of a traffic microsimulation. This set-up was created with the specific objective of evaluating the effects environment properties and road infrastructure designs on cyclists’ perceived safety. Forty participants, mainly university students, were recruited for the experiment. Results showed that the average speed of the participants changes between scenes with different bicycle facilities, with the highest value for the segregated bicycle path. The braking and head movement activities also changed within each scene, where they significantly occurred more before arriving at the intersections. Questionnaire results revealed adding a painted bicycle path to a sidewalk increases the level of perceived safety. Moreover, participants felt safest for cycling on the segregated bicycle path, in line with findings from previous research. This study provides evidence that cyclists’ behavior and perceptions in VR is very similar to reality and that VR, combined with a cycling simulator, is suitable to communicate (future) cycling facilities.
  • Operator and user perspectives on fleet mix, parking strategy and drop-off bay size for autonomous transit on demand
    Item type: Working Paper
    Wang, Biyu; Ordoñez Medina, Sergio A.; Fourie, Pieter J. (2018)
    Arbeitsberichte Verkehrs- und Raumplanung
    Autonomous vehicles (AVs), but in particular shared autonomous transit on demand (ATOD), promises many efficiencies in future transport provision, and may lead to concomitant changes in urban form. Considering the effects of car-oriented planning on the livability, efficiency and sustainability of 20th century cities, there is growing interest in how we may anticipate the changes that this disruption will bring about. Parking is one of the several vehicle behaviors which may be reformed by the upcoming era of AVs. In the paper, four different parking strategies as well as bay constraints are implemented to assess the influence of possible parking regulations on ATOD. Four parking strategies are explored, including demand-based roaming, parking on the street, parking in depots and mixed parking between parking on the street and in depots. We tested bay sizes of 10, 15, 20, 25, and 30m, for a mix of 3 vehicle sizes: 4-, 10 and 20-seaters. Combinations of different parking strategies and different bay sizes were evaluated from the perspective of travel time, walk distance, vehicle occupancy and vehicle kilometers traveled. Results show that strategies produce radically different utilizations of vehicles to provide the same minimum service level for a particular study area in Singapore. We conclude that urban designers and policy-makers need to consider these as important parameters when designing or retrofitting neighborhoods if they want to maximize potential benefits from this new transportation mode.
  • Privacy-by-design generative models of urban mobility
    Item type: Working Paper
    Anda, Cuauhtémoc; Ordonez Medina, Sergio Arturo (2019)
    Arbeitsberichte Verkehrs- und Raumplanung
    New streams of Location-based Services (LBS) Big data have risen society’s concerns in regards to data privacy. Even though these type of data sets are anonymised and aggregated in space and time, the risk of a privacy breach by user’s re-identification is still imminent. Still, LBS data has the potential to improve current travel demand models and transportation applications. We this in mind, we introduce a Privacy by Design framework that generates realistic disaggregated daily mobility patterns without the need for any personal information or access to individual-level LBS data. On the first step of the framework, we estimate the joint probability distribution of daily mobility patterns using modified Markov models, followed by an adaptation of the rejection sampling algorithm to improve the distribution of the daily tour types. We validate the synthetic mobility patterns against six different distributions and reach an average accuracy over 95%. With this, we hope to open the discussion in the transportation community in regards to data privacy and travel demand models.
  • Implications of autonomous vehicles on urban form and transport supply
    Item type: Report
    Fourie, Pieter J.; Maheshwari, Tanvi (2018)
    Arbeitsberichte Verkehrs- und Raumplanung
    With continued development and intensification of Singapore, the challenges of increased car usage, traffic congestion, as well as the availability of land for roads become more pressing. A future Singapore that is both sustainable and liveable will need to reduce reliance on cars and work towards a car-lite future, a principle that was endorsed by Prime Minister Lee Hsien Loong in the Singapore Sustainable Blueprint 2015.
Publications 1 - 6 of 6