Listen
7 Ergebnisse
Ergebnisse nach Hochschule und Institut
Publikation Simulation of policies for automated ride-hailing and ride-pooling services(05.01.2025) Kagho, Grace; Balac, Milos; van Eggermond, Michael; Erath, AlexanderAutomated vehicles are becoming more prevalent, and the disruption they would cause in combination with ride-hailing and ride-pooling services could be tremendous. Therefore, this study investigates the impacts of ride-hailing and ride-pooling automated fleets in two Swiss cities, Chur and Zurich, and potential policy measures to steer their operations towards more sustainable solutions. We employ the results of the stated preference survey and combine the estimated mode-choice and car ownership model results with the agent-based simulation, MATSim, to simulate the impacts of various scenarios. We find that automated ride-hailing (aRH) and automated ride-pooling (aRP) services do not seem to be competing for the same demand. In general, these services would lead to a reduction in total travel time but an increase in total vehicle distance, which is more substantial in transit-oriented Zurich than in car-oriented Chur. Furthermore, we found that even though the proposed policies increased vehicle occupancy, they did not manage to overcome the increase in VKT, signaling the need for more targeted policies and operational strategies. Finally, we provide recommendations for transport policy and future research based on our findings.04B - Beitrag KonferenzschriftPublikation Comparing Q347 development and regionalization using recent data in two Swiss cantons(09.11.2024) Dups, Yanick; Lebrenz, HenningIn Switzerland, low flows are characterized by the discharge level corresponding to a 95% exceedance probability on a ten-year average flow duration curve, referred to as Q347. This threshold not only has significant implications for planning but also requires authorities to adjust the operation of relevant infrastructure to mitigate ecological impacts on watercourses. The value of Q347 can be determined from a flow duration curve if a discharge time series of at least ten years is available. However, for smaller catchments such time series are typically unavailable, necessitating the regionalization of Q347 values. In Switzerland, multiple linear regression has been established to estimate the area-specific discharge q347 for ungauged basins. The primary objective of this study was to regionalize Q347 values for small, ungauged catchments (383 in the Canton of Solothurn and 9'034 in the Canton of Zürich) each with an area of less than 100 km². Daily discharge, precipitation, and temperature time series were collected for a 30-year study period from 1990 to 2020 from 56 gauged catchments in Solothurn, and similarly for a ten-year study period from 2013 to 2023 in Zürich, focusing on catchments smaller than 500 km² surrounding the target areas. A total of 30 “static” parameters delineating geometry, topography, geology, land use, and drainage along with nine “climatic” parameters describing temperatures, precipitation distributions, and potential evapotranspiration were defined and computed to characterize both gauged and ungauged catchments. The temporal variability of low flow events was then analysed for observed catchments in the two study areas. Over the past 30 years, the frequency of low flow events below the threshold has systematically increased, while the ten-year Q347 values for these catchments have decreased during the same period. Three multiple linear regression methods were developed and implemented to be coupled with two adjustment techniques supplementing truncated discharge time series. Validation of the proposed models showed reduced errors and increased linear correlations between estimated and observed values compared to standard models. Notably, a spatially more homogeneous yet catchment-specific distribution of estimated values is observable. The proposed models yielded promising results, particularly when time series remain unadjusted, or adjustment is done using the Antecedent Precipitation Index (API) combined with the flow duration curve of a donor basin (Ridolfi et al., 2020). Using recent data for parameter selection and model fitting, especially in the Zürich study area (2013-2022), often resulted in lower Q347 values compared to standard models, reflecting an adaptation to current climatic trends.06 - PräsentationPublikation Virtual reality and choice modelling. Existing applications and future research directions(Edward Elgar Publishing, 2024) van Eggermond, Michael; Mavros, Panos; Erath, Alexander; Hess, Stephane; Daly, AndrewResearch eliciting individuals’ preferences, including stated preference (SP) research, have long utilised imagery as stimuli to visualise either attributes or situations deemed too complex to be expressed verbally. The advent of Virtual Reality (VR) offers choice modelers with exciting new opportunities. This chapter outlines key concepts underlying VR and summarises previous research combining VR and choice modeling. It provides a framework of different dimensions that should be considered when developing VR experiments, including technological aspects (display technology and movement) and other aspects, such as survey duration, motion sickness and the representation of time. The chapter concludes with several ways to further combine choice modeling and VR.04A - Beitrag SammelbandPublikation Nachhaltige Ansätze zur Parkraumplanung(Bundesamt für Strassen, 09.07.2024) Erath, Alexander; van Eggermond, Michael; Sieber, Mark; Graf, Samuel; Perret, Fabienne05 - Forschungs- oder ArbeitsberichtPublikation Analysis of the resolution of precipitation data required to obtain robust results from a hydrodynamic sewer network model(19.04.2024) Rabiei, Ehsan; Hoppe, Holger; Lebrenz, HenningThe need for precipitation data for calibrating hydrodynamic sewer network models is often compromised by using the nearest available rain gauges to study area. Due to the scarcity and irregular locations of the rain gauges, this way of satisfying the need for precipitation data can lead to incorrect conclusions with respect to the temporal and spatial patterns of precipitation, depending on the location of the rain gauges in the study area. Recent developments in the field of precipitation measurement by means of weather radar data open up new possibilities for the use of such data sources in hydrodynamic sewer network models. Even though weather radar provides precipitation information with a high temporal and spatial resolution, the raw radar data contains several sources of error and is inaccurate. The radar data are therefore often corrected and merged with ground measurements. The main objective of this study is to investigate the resolution of precipitation data required to obtain robust results in a hydrodynamic channel network model. The study area is a small catchment close to Munich in Bavaria, Germany. Data from the Isen weather radar station of the German Weather Service (DWD), which is located around 33 km from the study area, was used. Following the objectives of this study, various weather radar data products were processed in order to be used as input for a hydrodynamic sewer network model. The data with a temporal resolution of 5 minutes to 1h and a spatial resolution of 250 m x 250 m up to 1.000 m x 1.000 m form the basis for creation of datasets to be investigated. It has been observed that the use of high-resolution precipitation data leads to better model results, especially when the data is merged with rain gauges. However, it should be noted that the quality of the model results does not decrease linearly when the resolution of the precipitation data is reduced.06 - PräsentationPublikation Physikalische Modellierung des Geschiebetransports für «WieseVital»(Schweizerischer Wasserwirtschaftsverband, 03/2024) Venuleo, Sara; Unrau, Silas; Guido Derungs; Lebrenz, HenningDas Revitalisierungsprojekt «WieseVital» (BS) sieht den Einbau einer grobkörnigen Schutzschicht über die gesamte Gewässersohle sowie punktuell eingebrachtes, feinkörniges Laichsubstrat vor. Um die Interaktion der beiden Kornfraktionen, insbesondere den Einfluss der Feinsedimente auf die grobkörnige Schutzschicht zu beurteilen, wurde an der Fachhochschule Nordwestschweiz (FHNW) ein physikalisches Wasserbaumodell im Massstab 1:20 nachgebaut. Unter Beachtung von Skalierungseffekten und den abgeleiteten Rand- und Übertragungsbedingungen, konnten wertvolle Grundlagen und Hinweise für den Bau und den Betrieb des geplanten Flussabschnitts gewonnen werden. Das eingebrachte feinkörnige Laichsubstrat verteilt und vermischt sich bis zur Vermischungstiefe, die durch «kinetische Siebung» (z. B. beim HQ100) deutlich erhöht werden kann. Im Allgemeinen erleichtern die Feinsedimente den Bewegungsbeginn der grobkörnigen Schutzschicht, ohne allerdings ihre Stabilität zu gefährden. Ergänzend können erhöhte Kolkbildungen an geplanten ökologischen Einbauten durch lokale Sohlsicherungsmassnahmen begrenzt werden. Im späteren Betrieb kann das Modell von Wilcock & Crowe für die Abschätzung der gesamten Geschiebefracht angewendet werden, falls die raumzeitliche Verteilung der notwendigen Gewässersohleneigenschaften bekannt ist.01B - Beitrag in Magazin oder ZeitungPublikation Neue Abschätzungsmodelle zur Bestimmung des Q347(Schweizerischer Wasserwirtschaftsverband, 2023) Dups, Yanick; Santolamazza, Daniela Pavia; Staufer, Philipp; Lebrenz, HenningNiedrigwasserperioden können mit dem Q347 (5-Prozent-Quantil) beschrieben werden. Die Unterschreitung dieses Schwellenwertes hat Auswirkungen auf die Planung und den Betrieb relevanter Infrastruktur, auch um die ökologischen Auswirkungen in den Fliessgewässern zu reduzieren. In dieser Studie werden für die gletscherfreien Einzugsgebiete des Untersuchungsgebiets um den Kanton Solothurn die zeitliche Variabilität der Unterschreitungsereignisse analysiert und neue Abschätzungsmodelle des Q347-Wertes für unbeobachtete Einzugsgebiete vorgestellt. In den letzten 30 Jahren ist ein vermehrtes Auftreten der Unterschreitungstage, bzw. eine systematische Abnahme der Q347-Werte aufgrund von Klimawandel, zu beobachten. Auch ist die Eintrittswahrscheinlichkeit der Niedrigwasserperioden mit zunehmender Er-eignisdauer für spätere Sommermonate am höchsten. Des Weiteren schlagen wir neue Regressionsmethoden zur Ab-schätzung des Q347 für unbeobachtete Einzugsgebiete vor. Wir vergleichen drei Verfahren zur Auswahl von geeigneten Parametern und evaluieren drei Regressionsmodelle in Kombination mit zwei Anpassungsmethoden zur Ergänzung verkürzter Zeitreihen des gemessenen Abflusses. Die Validierung ergibt, dass die vorgeschlagenen Modelle kleinere Fehler und grössere, lineare Zusammenhänge zwischen Schätz-und beobachtetem Wert erzeugen als die Vergleichs-modelle. Die Anwendung auf die «Einzugsgebietsgliederung Schweiz» zeigt eine räumlich homogenere, aber EZG-spezifische Verteilung des Q347. Diese sollte als Beitrag zur Bewältigung der zukünftigen Herausforderungen in der Was-serwirtschaft angesehen werden.01B - Beitrag in Magazin oder Zeitung