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- Bagdadi, Omar
(författare)
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The development of methods for detection and assessment of safety critical events in car driving
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Improving our knowledge of drivers’ behaviour, especially in hazardous situations is a key to understanding why accidents occur and how to improve safety on our roads. Crash surrogate measures have proven to be very useful in traffic safety analysis. As a valid crash surrogate measure shares the same logical chain of events as actual crashes, studying those events increases the opportunities to analyze external circumstances as well as events and driver behaviour preceding the crash. A new definition of crash surrogate measures is proposed, i.e. safety critical braking events: Situations (including crashes) that require a sudden, evasive manoeuvre to avoid a crash or to correct for unsafe acts performed by the driver himself/herself or by other road users. This thesis develops a method for detecting Safety CRItical Braking Events (SCRIBE) and evaluates against other methods mostly used in large naturalistic driving studies. The evaluation shows promising results in the success rates of detecting safety critical events. Further, a Method for estimating the SEverity of safety Critical events (M-SEC) involving more than one road user, is developed and evaluated. The method combines a measure of closeness-to-collision, or safety margins, with a measure of possible consequences based on the speed and mass of the involved road users. Besides, a comparison is made with the Traffic Conflict Technique. Evaluation of the method shows that the estimated severity using M-SEC enables comparison of safety critical events involving different types of road users and is not limited to comparisons between similar types of events. In addition, the estimations when using M-SEC seem to reflect the seriousness of the safety critical events.
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| 2. |
- Sochor, Jana
(författare)
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Impacts of Intelligent Transportation Systems on Users' Mobility: A Case Study Analysis
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- People have many reasons to be mobile, from day-to-day activities involving work, studies, and family, to maintaining participation in society, health, and quality of life. Information and Communication Technology (ICT) is increasingly being deployed in the transportation context to improve individuals' mobility; for example via information provision. Advanced use of ICT in transportation is commonly referred to as Intelligent Transportation Systems (ITS).Despite many opportunities for ITS services to enhance personal mobility, the collection and use of movement and activity data also poses challenges, as it facilitates easier access to more information for people to use, but about them as well. Knowledge about users' perceptions of advantages and disadvantages (for example assurance and privacy) associated with the use of ITS services is limited. Even less is known regarding to what degree their perceptions influence their acceptance of the services or their behavior.The aim of this thesis project is to gather empirical interview and survey data from multiple user groups in order to learn more about the factors impacting users' attitudes towards ITS services. In exploring not only demographic factors, but also the potential positive and negative impacts from the users' perspective, this project attempts to paint a more holistic view of the issues surrounding the possibilities for ITS to enhance mobility.From the two case studies presented in this thesis, results indicate that respondents are pro-technology and are not highly concerned about privacy in general, but other ethical issues serve to shed light on the situations of different user groups. In the first case study with visually impaired individuals, the ability to lead an autonomous and independent life is a strong driver for the acceptance of a pedestrian navigation system, which the users themselves would choose to use. While the participants are generally optimistic about the possibilities of using ITS to enhance their mobility, their comments illustrate that ICT development does not necessarily result in ethically sound, universally accessible technology, and that a coordinated effort on multiple fronts is vital in addressing users' needs and meeting broader social goals such as social inclusion and the accessibility of transportation, technology, and information.In the second case study with professional heavy goods vehicle drivers and their employers, the drivers are in a dependent (employee) position and have less personal control over the use of ITS services in the vehicles. The employers are perceived as the greater beneficiaries of the services, which could be linked to the systematic lack of feedback to the drivers. Generally, the respondents trust the employers to protect the drivers' privacy. However, there also exist gaps in organizational communication regarding data gathering and handling practices as well as in expected versus stated behavior modification as a result of workplace monitoring. As employees are not normally able to provide informed consent due to their dependent position, recommendations for organizations include performing comprehensive impact assessments, engaging in an ongoing dialogue with employees, and providing an opt-out option in order to move towards a more informed consent.
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