The diploma thesis deals with a data analysis of the Formula Student race car. An attention is given for both, vehicle and driver. Processes of braking, turning and balance of car are analysed. Special attention is given to the dampers positions while driving and their settings. Dampers velocity histograms and ride frequencies graph are put together. Algorithms in MATLAB are suggested to reduce requested time for analysis. Scripts for displaying important channels are made. Analyzed data are used to create events which accelerate orientation in record and tell the most important information.

Most tyre models developed to date require a fair amount of data before an accurate representation of the tyre can be obtained. This study entails the development of a simplified, yet accurate, non-linear Finite Element (FE) model of an “off-road” tyre to study the behaviour of the tyre due to radial loading conditions. The study aims to develop a FE tyre model that can solve fast and be accurate enough to be used in multibody dynamic vehicle simulations. A model that is less complex than conventional detailed FE models is developed. The work explores the use of superimposed finite elements to model the varying stiffness in the respective orthogonal directions of the sidewall and tread of the tyre. Non-linear elements defined by Neo-Hookean or Ogden models and elements with different linear orthogonal stiffnesses are superimposed onto each other to simulate the global material properties of the tread and the sidewall of the tyre investigated. The geometry of the tyre studied was measured experimentally using laser displacement transducers and digital image correlation techniques. Material properties of segments of the tyre were obtained by performing tensile tests on samples. Since the rubber slipped against the clamps during the experiment, deformation of the segments was also measured using digital image correlation. These geometrical and material properties were used as input to develop a finite element model of an “off-road” tyre. Measurements were conducted using laser displacement transducers, load cells mounted to actuators, etc. to obtain accurate sidewall deformation profiles and global radial load vs. displacement curves for different radial loading conditions. The data obtained from the results was used to validate the tyre model developed. Numerous analyses are performed with different combinations of moduli of elasticity in the respective orthogonal directions of the sidewall stiffness and the tread to investigate its influence on the global behaviour of the tyre model. The main focus of the project was to develop a tyre model from data obtained from laser and photogrammetry measurements in a laboratory that accurately represents tyre behaviour due to radial forces. A finite element model that can simulate the effect of radial forced and obstacles on a tyre was developed. The use of two subsets of elements, superimposed onto each other to simulate global material properties of the rubbers, steel wires, polyester and nylon threads, was investigated. The combination of material properties that gave the best fit for all the load cases investigated were determined. The finite element model correlated well with the load vs. displacement graphs and sidewall displacement profiles determined experimentally. The solving time is still fairly high and is still not quite suitable for real-time dynamic simulation. However, it solves faster than more complex tyre models where details of steel wires, etc. are included in the model. For future studies it is recommended that different element types be investigated in the tyre model. The study proves that equivalent material properties can be used to simulate the composite properties of the materials in tyres. Most tyres can be divided into a few regions that each has its own material structure right through the region. These regions can be characterized by simple tests and the input can be used as a first estimation of the tyre’s material properties for the model. Accurate validation criteria should be used to validate the tyre model if time does not allow for excessive testing of the material properties of all the rubber, steel wires, polyester threads, etc. Geometric displacement data at various loading conditions can be used for validation of the tyre model. The model developed can be used to investigate the effect of different stiffnesses and other material changes in the sidewall or tread of a tyre. Useful insight can be obtained from the finite element model developed for dynamic simulation where the force vs. global displacement data is important. / Dissertation (MEng)--University of Pretoria, 2014. / tm2015 / Mechanical and Aeronautical Engineering / MEng / Unrestricted

The focus of this thesis is to study what and how information flows can be used to improve Demand responsive transport (DRT) systems by understanding potential users and how they could be willing to participate in DRT to a higher degree. The viewpoint of this thesis tends to lean towards a DRT service of a public transport type. This thesis studies users in relation to what interaction and information they perceive to be needed in dealing with a DRT service and the different pros and cons with various approaches. The study gathers information by performing adapted qualitative interviews with a select number of users between the ages of 20-35. The participants give their views on three DRT scenarios and reflect on DRT in general as a concept presented to them through a tangible mocked-up interactive prototype.  The thesis makes several distinct findings. The importance of pricing a DRT service correctly is vital to the users, as several participants in the study relied on pricing for decision-making. It also finds that the usage of zones as nomenclature is confusing to many users. The services must be dependable and punctual to both attract users, keep users, and build trust among the general populace. This study shows that DRT services could be a difficult concept to introduce to users. DRT could be introduced as a complement or as an alternative to conventional public transport. An important factor is a well-designed flow of information in the application to keep the user engaged and involved. It is shown that the usability of the application is a cornerstone for a theoretical DRT service to excel. Context is important where DRT and ridesharing would have a higher success rate. Nighttime in urban areas could be a niche market, due to the irregularity, delay, or interruption of regular public transport services at these hours.

The passenger transportation sector is notoriously difficult to decarbonize. In this thesis, two distinct and novel methodologies to estimate the environmental impact of alternative and conventional transportation technologies are developed. In Chapter 2, a provincial fleet policy-driven linear programming model is developed to minimize the cost of three passenger vehicle electrification policies in Ontario under a 30% GHG reduction target by 2030. Provincial life-cycle emissions and total-cost-of-ownership associated with policy allocation is estimated. The results highlight that electrification of on-road passenger transportation will not be sufficient to meet the 30% reduction target despite Ontario's low-carbon electricity grid. Instead, reductions of between 24% to 26% are forecasted at an annual cost (for ten years) of between CAD 0.29 to 0.3 billion annually indicating that additional policies are necessary to realize a 30% reduction target. In Chapter 3, a trip-level vehicle framework is developed to determine under what operating conditions transit buses and passenger cars will be environmentally beneficial across the dimensions of technology, service mode, and power source pathway. The well-to-wheel energy consumption and GHG emissions are simulated for over 450 operating scenarios. Emissions are then normalized through passenger-trip emission thresholds to facilitate equivalent comparison across all dimensions. The results indicate that the most beneficial solution are fuel-cell electric car-share, battery electric car-share, and battery electric bus all powered by low-carbon intensity power sources at average occupancy (7.9-19.7 gCO2e passenger-service-mode-trip-km-travelled-1). Furthermore, transit bus technologies have the potential to reduce up to 2.3 times more GHG per passenger-trip than comparable ride-share passenger cars at average occupancies. The results of Chapter 2 and 3 highlight that technology alone may not be sufficient to achieve significant GHG reductions; policy which leverage local operating data and target GHG reduction associated with passenger-trips are critical to informing under what conditions a mobility solution is environmentally beneficial. / Thesis / Master of Civil Engineering (MCE) / There is a dire need to evaluate the effectiveness of transportation GHG mitigation policies as alternative mobility solutions are being adopted and the pressure to respond to climate change intensifies. This work evaluates the effectiveness of policy optimization and vehicle-level simulation techniques to inform GHG mitigation decision-making. A two-step approach is adopted herein. At the strategic level, a cost optimization model for passenger vehicle electrification policies in Ontario is calibrated to identify the optimal allocation of provincial policy to achieve a 30% GHG reduction by 2030. Next, a micro level focuses on the energy consumption of eight vehicle technologies over 450 operational scenarios is simulated and trip-level passenger emissions are estimated to reveal the environmentally beneficial mobility option, corresponding passenger thresholds, and extent of variability associated with local operating conditions. Overall, optimization and trip-level vehicle simulation can be used to demystify optimal decision-making related to mobility solutions.

El sector del transporte y la movilidad está experimentando profundas transformaciones debidas principalmente a la concienciación medioambiental, al aumento de la población de las grandes áreas urbanas y al tamaño de las ciudades, al envejecimiento de la población y la aparición de relevantes innovaciones tecnológicas que han cambiado los hábitos de consumo, como el comercio electrónico o la economía colaborativa. Así, el auge de aplicaciones móviles como Uber y Cabify están transformando la movilidad urbana y metropolitana que debe adaptarse a este nuevo escenario y al propio concepto de movilidad. Estas aplicaciones ofrecen una alternativa a las prestaciones que tradicionalmente ha brindado el sector del taxi y el alquiler de vehículos con conductor (VTC), y se han desarrollado en un contexto de regulación de los mercados del taxi y VTC que contienen importantes restricciones no justificadas a la entrada y ejercicio de la actividad en el mercado, entre las que destaca el numerus clausus de licencias, el limitado ámbito geográfico de la licencia y, para el caso del taxi, los precios regulados en forma de tarifas públicas no flexibles. En este estudio, y aprovechando los últimos cambios legislativos que afectan sobre todo a la prestación de servicios de estas plataformas en España, se ha analizado cómo ha impactado su implantación en la seguridad vial de Madrid en dos periodos temporales diferenciados (2014-2018 y 2013-2019). En primer lugar, se ha analizado cómo ha afectado la entrada de estos servicios en la frecuencia de los accidentes -con al menos un herido grave o muerto-, diferenciando entre accidentes con presencia de alcohol o drogas y accidentes producidos en fin de semana y festivo. En segundo lugar, y teniendo en cuenta que por cada muerte en las carreteras europeas se producen unas cuatro lesiones que incapacitan de forma permanente, como daños en el cerebro o la médula espinal, ocho lesiones graves y cincuenta lesiones leves, se ha analizado el impacto de estos servicios en la gravedad del accidente, considerando el número de víctimas totales, heridos graves y muertos y heridos leves. Por último, y considerando que este tipo de servicios puede contribuir a una transferencia desde el vehículo particular a otros modos de transporte, fomentando la intermodalidad y cubriendo la "última milla" de los servicios de transporte más rígidos, dotando de mayor capilaridad y alcance a las redes troncales de transporte colectivo, se ha analizado si estos servicios complementan o sustituyen al transporte público para reducir la accidentalidad. Para ello, se ha realizado un análisis de regresión utilizando un modelo binomial negativa de efectos aleatorios (RENB). Se ha escogido el municipio de Madrid por razones relacionadas con la oferta de servicios y disponibilidad de datos suficientes para formular el modelo matemático. Los resultados muestran que desde la llegada de Uber y Cabify al municipio de Madrid los accidentes -con al menos un herido grave o muerto- y con presencia de alcohol o drogas se han reducido en torno al 98%. Del mismo modo, también se observa un descenso, de aproximadamente un 18%, en el número de accidentes -con al menos un herido grave o muerto- producidos en fin de semana y festivo. Respecto a la gravedad del accidente, los resultados obtenidos muestran una reducción en el número de heridos graves y muertos de entorno al 25%. Sin embargo, el número de víctimas totales y el número de heridos leves ha aumentado un 3% y un 5% respectivamente. Finalmente, se ha observado que el número de heridos graves y muertos ha disminuido tanto en la "Almendra Central" (30.5%) como en la periferia (54.9%) del municipio, siendo mayor el impacto de estas plataformas en los distritos periféricos -con menor presencia de transporte público-. Además, el número de accidentes (con al menos un herido grave o un muerto) en fin de semana y festivo ha disminuido en ambas zonas, siendo de nuevo el impacto más notable en las zonas periféricas con un 54.9% frente a un 49.7%. El número de heridos leves también han disminuido en los distritos periféricos de la ciudad un 24,6%. Sin embargo, el número de heridos leves ha aumentado un 5.7% en la "Almendra Central" donde el 73% de los desplazamientos se realizan en transporte público. En general, los resultados encontrados en este estudio apoyarían la hipótesis de que estos servicios sustituyen al transporte público, en especial a los autobuses urbanos. Sin embargo, estos servicios mejoran la oferta a los usuarios con mayores dificultades para acceder a los taxis o al transporte público, constituyendo un modo de transporte alternativo para los conductores de alto riesgo. Por lo tanto, estos hallazgos pueden ser muy útiles para que los responsables políticos definan mejor las políticas reguladoras de estos servicios.

When striving to develop towards sustainability, reducing private car use is a crucial factor. The most convenient alternative is to replace the private car with public transport. Fast public transport types, such as trains, have large catchment areas, thus walking to the station can be time consuming and increases door-to-door travel time compared with the private car. An alternative to this is bike-and-ride, i.e. cycling to the transit station and continuing with public transport. This study aims to find ways to increase public transport use, focusing on cycling between the home and the transit station. This is done through a literature study and a case study in Knivsta, a suburban area of Stockholm connected to the city center through commuter trains. Improvements in the current bike-and-ride infrastructure in Knivsta are suggested, using the principles of Transit Oriented Development and Theory of Planned Behavior as guidelines. The most important aspects of high bike-and-ride proportions is the provision of separate bicycle paths and plentiful high-quality bicycle parking at transit stations. The current situation in Knivsta is inadequate with few separate bicycle paths and the bicycle parking does not fulfil recommendations. Suggestions for improvements are proposed, with developing a regional bicycle highway network in addition to other bicycle paths throughout the town of Knivsta, in addition to increased and improved bicycle parking at Knivsta train station to fulfil the requirements of the future as Knivsta is expected to double in population towards 2030. The changes proposed to the bicycle infrastructure in Knivsta have potential to increase public transport use, decreasing private car and park-and-ride use. Due to the bicycle network being convenient and accessible for virtually everyone, the municipality will develop towards environmental, economic, and social sustainability.

Sharing automated vehicles (AVs) is a possible future, where shared automated vehicles (SAVs) and pooled automated vehicles (PooledAVs) are prospective on-demand AV configurations. While SAVs and PooledAVs can contribute to the sustainability of transport systems, the success of on-demand AVs depends on whether and how the public adopts them as regular travel modes. As such, this dissertation investigates five objectives: (1) to scrutinize the essential steps of designing a future mobility survey , while the primary focus of the survey is on respondents’ intentions to adopt various AV configurations (2) to propose and validate a theoretical model for on-demand AV adoption by extending the Theory of Planned Behavior (TPB), (3) to identify the prospective use cases of SAVs as the potential precursor of on-demand AVs, (4) to identify individual characteristics that may trigger different behavioral intentions among the on-demand AV service types, and finally (5) to investigate Canadians’ intentions to adopt on-demand AVs. A nationwide Canadian survey was designed and administered in fall 2021 (n = 5002) among adults (18 to 75 years old) residing in six major Canadian metropolitan areas: Toronto, Vancouver, Ottawa-Gatineau, Montréal, Calgary, and Hamilton. The findings of this dissertation paint a complex picture of on-demand AV adoption in the Canadian context with respect to the application of constructs from common technology adoption models and will help researchers investigating the characteristics of prospective consumers of on-demand AVs to identify the importance of affective motivations regarding adopting such emerging travel modes. The results reveal that many Canadians are yet either uncertain or reluctant to adopt AV technology in shared mobility services. In this light, policymakers and planners should adjust and moderate their expectations regarding the future market for on-demand AVs and be prepared for potential changes in travel behavior by examining incremental changes in existing on-demand ride-hailing services. / Dissertation / Doctor of Philosophy (PhD) / This dissertation assesses the conditions under which Canadians are willing to use fully automated vehicles (AVs) and investigates public perceptions and intentions to use “automated ride-hailing services,” which function as a taxi or Uber/Lyft service without a driver, and “pooled automated ride-hailing services,” which are a form of ride-hailing services, where passengers share a ride with someone they do not know to save on the cost of travel. To this end, an online survey (n = 5002) was designed and administered in October and November 2021 across six major Canadian metropolitan areas: Toronto, Vancouver, Ottawa-Gatineau, Montreal, Calgary, and Hamilton. Overall, results suggest that expectations towards AVs suddenly transforming the entire transportation sector, should be moderated and “automated ride-hailing services” and “pooled automated ride-hailing services” (when they are available in the entire Canadian market) are likely to be adopted as a supplementary mobility tool rather than a substitution for current travel modes.

This dissertation, comprised of three essays, investigates the behavioral aspects and social dynamics impacting service providers and consumers in sharing economy, with a particular focus on ride-hailing services. The first essay, informed by general deterrence theory and protection motivation theory, investigates the behavioral factors influencing the operational performance of sharing economy service providers, specifically within the ride-hailing industry, by surveying drivers. The second essay, drawing upon social identity theory, explores the effects of rider-driver ethnicity alignment on drivers' anticipated ride satisfaction, willingness to perform, and riders' trust in the driver through scenario-based online experiments with ride-hailing drivers and riders. The third essay presents a bibliometric review of existing literature on ride-hailing services to explore research trends, theoretical underpinnings, and also to identify research gaps and future opportunities in the fields of supply chain and operations management. Taken together, the three essays in this research enhance our comprehension of the behavioral factors affecting service providers and consumers within the sharing economy. As a result, both theoretical and managerial insights are generated, contributing to the existing supply chain literature.

Noise and vibration transmitted through the tire and suspension system are strong indicators of overall vehicle ride quality. Often, during the tire design process, target specifications are used to achieve the desired ride performance. To validate the design, subjective evaluations are performed by expert drivers. These evaluations are usually done on a test track and are both quite expensive and time consuming due to the several experimental sets of tires that must be manufactured, installed, and then tested on the target vehicle. In order to evaluate the performance, expert drivers tune themselves to the frequency response of the tire/vehicle combination. Provided the right models exist, this evaluation can also be achieved in a laboratory. The research presented here is a method which utilizes the principles of frequency based substructuring (FBS) to separate or combine frequency response data for the tire and suspension. This method allows for the possibility of combining high fidelity tire models with analytical or experimental suspension data in order to obtain an overall response of the combined system without requiring an experimental setup or comprehensive simulations. Though high fidelity models are not combined with experimental data in the present work, these coupling/decoupling techniques are applied independently to several quarter car models of varying complexity and to experimental data. These models range from a simplified spring-mass model to a generalized 3D model including rotation. Further, decoupling techniques were applied to simulations of a rigid ring tire model, which allows for inclusion of nonlinearities present in the tire subsystem and provides meaningful information for a loaded tire. By reducing the need for time consuming simulations and experiments, this research has the potential to significantly reduce the time and cost associated with tire design for ride performance. In order to validate the process experimentally, a small-scale quarter car test rig was developed. This novel setup was specifically designed for the challenges associated with the testing necessary to apply FBS techniques to the tire and suspension systems. The small-scale quarter car system was then used to validate both the models and the testing processes unique to this application. By validating the coupling/decoupling process for the first time on the tire/vehicle system with experimental data, this research can potentially improve the current process of tire design for ride performance. / Ph. D. / Noise and vibration transmitted through the tire and suspension system of a vehicle strongly influence the comfort of passengers. Often, during the tire design process, target specifications are used to achieve the desired vibrational characteristics. Subjective evaluations are then performed by expert drivers in order to validate the tire design. These evaluations are usually done on a test track and are both quite expensive and time consuming due to the several experimental sets of tires that must be manufactured, installed, then tested on the target vehicle. The research presented here utilizes techniques from the field of Dynamic Substructuring which allow frequency data for the tire and suspension systems to be separated or combined. This method allows for the possibility of combining high fidelity tire models with analytical or experimental suspension data in order to obtain an overall response of the combined system without requiring an experimental setup or comprehensive simulations. Several analytical tire and suspension models were developed for this work and the process of separating/combining the frequency data was performed. Then, a small scale test system was developed and used to establish experimental procedures to collect the data necessary to carry out the Dynamic Substructuring techniques. Finally, the process was validated by repeating the process of separating/combing the frequency properties of the experimental data.

The ride stability of an A-train 28-foot double tractor trailer when outfitted with different Roll Stability Control (RSC) systems with the same payload and suspension configurations is studied experimentally for various dynamic maneuvers. The primary goal of the study is to determine the effect of different commercially-available RSC systems on the extent of improvements they offer for increasing roll stability of commercial vehicles with double trailers, when subjected to limit-steering maneuvers that can rise during highway driving. A semitruck and two 28-foot trailers are modified for enduring the forces and moments that can result during testing. A load structure is used for placing the ballast loads within the trailers at a suitable height for duplicating the CG height of the trailers during their commercial use. Outriggers and jackknifing arresting mechanisms are used to prevent vehicle damage and ensure safety during the tests. The test vehicle is equipped with multiple sensors and cameras for the necessary measurements and observations. The analog and video data are time-synced for correlating the measurements with visual observation of the test vehicle dynamics in post-processing. An extensive number of tests are conducted at the Michelin Laurens Proving Grounds (MLPG) in Laurens, SC. The tests include evaluating each RSC system with different maneuvers and speeds until a rollover occurs or the vehicle is deemed to be unstable. The maneuvers that are used for the tests include: double lane change, sine-with-dwell, J-turn, and ramp steer maneuver. Both a steering robot and subjective driver are used for the tests. The test data are analyzed and the results are used to compare the three RSC systems with each other, and with trailers without RSC. The test results indicate that all three RSC systems are able to improve the speed at which rollover occurs, with a varying degree. For two of the systems, the rollover speed gained, when compared with trailers without RSC, is marginal. For one of the systems, there are more significant speed gains. Since most RSC systems are tuned for a conventional tractor-trailer, additional testing with some of the systems would be necessary to enable the manufacturers to better fine-tune the RSC control scheme to the dynamics of double trailers. / MS / The safety of driven semi-trailer trucks towing two trailers is analyzed in a study created to examine the behavior of the vehicle and its units during high speed, high maneuvering circumstances. The rolling over of a specific test truck is studied to study the ability of a common large vehicle to succeed in evasive or emergency maneuvers. Focus on the rolling over of a truck is placed in this project, as large freight vehicle rollovers are among the most popular and most dangerous type of accidents on highways today. A semi-trailer truck with two trailers, or double trailer vehicle, is instrumented with sensors and cameras to study several different characteristics associated with vehicle operation and conditions that incite rollover. The behavior of a double trailer vehicle is complicated due to the additional rotation joint between the adjacent trailers, where typical semi-trailer trucks (18-wheelers) only incorporate one: between the towing tractor and the towed trailer. Commercially available electronic appliances called Roll Stability Control (RSC) systems were designed to automatically control and apply the vehicle brakes under rollover conditions, and are installed and used individually to evaluate any improvements on the test vehicle’s ability to stay upright. Information regarding RSC system operation can be found. All vehicle testing is completed at a professional vehicle testing location in Laurens, SC and the same four test maneuvers are used to determine the effectiveness of each of the five RSC systems tested using data collected with the instrumented sensors. Different types of RSC systems exist due to different manners of operation, and are discussed in this document and analyzed. This project develops the conclusion that the five systems used during testing all improve vehicle stability, but provide differing results in doing so, largely due to their different operations. Therefore, commercially available RSC systems are proven to work differently and provide different results. Recommendations for further testing of RSC systems is provided. Although no recommendations are made regarding the tested RSC systems, the collected data show large, double trailer freight vehicles are more stable when using any of the tested commercially available RSC systems, especially during evasive maneuvering or emergency situations. These findings can bring immediate improvements to large freight vehicle operation and safety.