| 1. |
- Cosma, Giovanni, et al.
(författare)
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Way-finding lighting systems for rail tunnel evacuation: A virtual reality experiment with Oculus Rift
- 2016
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Ingår i: Journal of Transportation Safety & Security. - : Informa UK Limited. - 1943-9962 .- 1943-9970. ; 8:No. S1, s. 101-117
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Tidskriftsartikel (refereegranskat)abstract
- An experimental study has been conducted to investigate if a new and simple system, that is, stripes of high-bright dynamic green LED lights installed on the floor, can support people way-finding in smoke-filled railway tunnel evacuations. The impact of way-finding installations on people evacuation (intended as people movement paths and evacuation times) has been studied using Oculus Rift, a head-mounted display (HMD) device for virtual reality. Two different way-finding installation setups have been investigated. A rail tunnel evacuation scenario has been developed in a virtual environment and the behavior of 60 test participants has been observed (one control group with no installations available and two groups with either alternate or continuous high-bright dynamic green lights). Results show a positive impact of way-finding lighting installations on people evacuation safety. No significant differences have been found between the impact of dynamic alternate and continuous lights on participants' evacuation behavior. Both installation setups influenced movement paths of test participants during the evacuation process, that is, participants tend to walk closer to the lights.
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| 2. |
- Jomaa, Diala, 1978-, et al.
(författare)
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Effectiveness of trigger speed of vehicle-activated signs on mean and standard deviation of speed
- 2016
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Ingår i: Journal of Transportation Safety and Security. - : Informa UK Limited. - 1943-9962 .- 1943-9970. ; 8:4, s. 293-309
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Tidskriftsartikel (refereegranskat)abstract
- Excessive or inappropriate speeds are a key factor in traffic fatalities and crashes. Vehicle-activated signs (VASs) are therefore being extensively used to reduce speeding to increase traffic safety. A VAS is triggered by an individual vehicle when the driver exceeds a speed threshold, otherwise known as trigger speed (TS). The TS is usually set to a constant, normally proportional to the speed limit on the particular segment of road. Decisions concerning the TS largely depend on the local traffic authorities. The primary objective of this article is to help authorities determine the TS that gives an optimal effect on the Mean and Standard Deviation of speed. The data were systematically collected using radar technology whilst varying the TS. The results show that when the applied TS was set near the speed limit, the standard deviation was high. However, the Standard Deviation decreased substantially when the threshold was set to the 85th percentile. This decrease occurred without a significant increase in the mean speed. It is concluded that the optimal threshold speed should approximate the 85th percentile, though VASs should ideally be individually calibrated to the traffic conditions at each site.
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| 3. |
- Larcher, Martin, et al.
(författare)
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Effectiveness of finite-element modelling of damage and injuries for explosions inside trains
- 2016
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Ingår i: Journal of Transportation Safety and Security. - : Taylor & Francis Group. - 1943-9962 .- 1943-9970. ; 8, s. 83-100
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Tidskriftsartikel (refereegranskat)abstract
- The rail-bound sector has become a preferred target of terrorist attacks because of its vulnerability, and the most frequent way to carry out these attacks has been the use of explosive devices.The aim of this study is to investigate the effectiveness of modelling detonation effects inside train carriages using explicit finite element techniques. The numerical simulations consider fluid-structure interaction phenomena and several parametric studies are conducted. Carriage damage and injuries to the passengers are examined. Displacements in the model of the carriage structure do not vary greatly for small changes of the charge size, its location, or by open doors. Changing charge size, the location of the detonation, and door setting however had significant impact on the risk of eardrum rupture and fatality. Comparison of the simulation and real life data demonstrate a good agreement between the real and calculated displacements of the carriage, whereas the risk of death and eardrum rupture is slightly higher in the calculations. The model presented can reproduce a reliable actual situation if more parameters that influence injuries of blast waves were considered.
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