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- Chee, Pei Nen Esther, 1989-
(författare)
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Understanding Changes in Decision-making Processes to Adopt First-/Last-Mile Automated Bus Service
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This research investigates the changes in the interactions of objective factors (factors which are independent of perception e.g. socio-demographic characteristics), subjective factors (psychological factors which are inherent in individual), and user’s behavioural responses towards a new technology/service in response to actual experience with the technology/service. In specific, this research investigates the changes in decision-making parameters to adopt first-/last-mile automated bus service over three important adoption stages, as specified in diffusion of innovations theory: 1. decision (before any actual ride experiences), 2. implementation (first trial) and 3. continuation (after the first trial). Findings show that objective factors have both direct and indirect influences on users’ behavioural responses towards a new technology. There are dominant perceptions towards the technology among the same group of people with the same socio-demographic characteristics/travel characteristics/familiarity with the technology. However, the relationships between the objective factors with the associated perceptions are not stable when the users have gathered incomplete information about the technology. Decision made without complete information about the technology is subjected to logical fallacy. Consequently, the decision made is irrational and subject to changes after an individual gains complete information about the new technology/service through actual experience with the new technology/service. Actual ride experiences provide users complete information about the technology. As compared to the behavioural responses of first-time users, the behavioural responses of the adopters (users who continued with the service after the first trial) are stable and consistent. Also, reinforcement learning process was found to exist in the adopters of the first-/last mile automated bus service. The findings give strong evidence that users’ level of information about a new technology/service has a significant impact on the stability of the representation of both the objective and subjective factors. In conclusion, users’ level of information about a new technology/service has a crucial impact on the reliability of the representation of the objective factors and subjective factors identified from the travel behaviour studies of new technology/service like automated vehicle/bus. The decision made when users have incomplete information about a new technology is irrational and subject to changes. Hence, the representation of the objective factors and subjective factors identified from hypothetical studies in which the respondents lack real experience with automated vehicle/bus technology is unreliable. On the other hand, actual experience provides users with complete information about the new technology/service and allows users to learn about the technology/service. As a result, users can make a more rational decision hence the representation of the identified objective factors and subjective factors is reliable. As another contribution of this research, a systematic approach to obtain objective measurements from real-world pedestrian-automated bus interactions using LiDAR data is also demonstrated in this thesis. The approach developed can be used as the fundamental framework to measure the safety risk between a crossing pedestrian with an automated vehicle/bus. Also, the developed method is helpful to the designing of control algorithm of an automated bus due to the attainments of the actual pedestrians’ risk thresholds when they interact with an automated bus in the real-world setting.
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| 2. |
- Börjesson, Maria, 1974-
(författare)
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Issues in Urban Travel Demand Modelling : ICT Implications and Trip timing choice
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Travel demand forecasting is essential for many decisions, such as infrastructure investments and policy measures. Traditionally travel demand modelling has considered trip frequency, mode, destination and route choice. This thesis considers two other choice dimensions, hypothesised to have implications for travel demand forecasting. The first part investigates how the increased possibilities to overcome space that ICT (information and communication technology) provides, can be integrated in travel demand forecasting models. We find that possibilities of modelling substitution effects are limited, irrespective of data source and modelling approach. Telecommuting explains, however, a very small part of variation in work trip frequency. It is therefore not urgent to include effects from telecommuting in travel demand forecasting. The results indicate that telecommuting is a privilege for certain groups of employees, and we therefore expect that negative attitudes from management, job suitability and lack of equipment are important obstacles. We find also that company benefits can be obtained from telecommuting. No evidences that telecommuting gives rise to urban sprawl is, however, found. Hence, there is ground for promoting telecommuting from a societal, individual and company perspective.The second part develops a departure time choice model in a mixed logit framework. This model explains how travellers trade-off travel time, travel time variability, monetary and scheduling costs, when choosing departure time. We explicitly account for correlation in unobserved heterogeneity over repeated SP choices, which was fundamental for accurate estimation of the substitution pattern. Temporal constraints at destination are found to mainly restrict late arrival. Constraints at origin mainly restrict early departure. Sensitivity to travel time uncertainty depends on trip type and intended arrival time. Given appropriate input data and a calibrated dynamic assignment model, the model can be applied to forecast peak-spreading effects in congested networks. Combined stated preference (SP) and revealed preference (RP) data is used, which has provided an opportunity to compare observed and stated behaviour. Such analysis has previously not been carried out and indicates that there are systematic differences in RP and SP data.
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| 3. |
- Hajinasab, Banafsheh
(författare)
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A Dynamic Approach to Multi-Agent-Based Simulation in Urban Transportation Planning
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Reviewing previous studies on using computational models for analyzing the effect of transport policies on transportation systems shows that agentbased models have not been used much in spite of their great potential for simulating dynamic aspects of policy instruments and travel behavior. The main reason can be the need for a lot of input data which is hard to prepare for the modeler. This has led to limited use of agent-based models in previous studies and even in those studies the scope of simulation is limited to only particular scenarios. In this thesis, I proposed a general-purpose agent-based simulation model for urban transportation that supports simulation of a wide range of policy instruments. The proposed model is designed in a way that a large part of the input data can be generated automatically using online web-services. The thesis also reports an empirical study on using our proposed generalpurpose model together with on-line travel planners in agent-based simulation for predicting the effect of different policy instruments on travel behavior. The results from our empirical study showed that our generalpurpose agent-based model predicts 72% of the real travel decisions correctly. Furthermore, the results of the simulation for various scenarios and combination of them seem to be acceptable. Finally, we found out that the use of on-line services for data collection increases the speed and flexibility of the system for defining and running new scenarios. However, the scalability of using on-line services in simulation is constrained by limitations of online service providers. The main contributions of this thesis are a general-purpose agentbased simulation model for urban transportation and a novel approach to automatically generate input data to the simulation using online travel planners and other web-services. This novel approach mitigates the challenge of agent-based simulation as a data-intensive method. This can lead to more widespread use for agent-based simulation in solving complex and realistic transportation scenarios. Another contribution of this thesis is on visualization of simulation output. One of the main challenges of using simulation systems by transport planners and decision makers as end-users is to understand the complex output of the simulation. In this thesis, I empirically demonstrated how the usability of a freight transport simulation system is improved by adding a visualization module that illustrates the results of the simulation for the end-users.
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