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This paper deals with possibilities to update existing road tunnels in order to fulfill up to date requirements regarding structural fire protection. Besides the upgrading of tunnels with structural fire protection systems (like e.g. fire protection sheets) there is also the possibility of numerical investigations. In research projects carried out on behalf of the Federal Highway Research Institute (BASt) numerical investigations for the proof of sufficient structural fire protection have been done for common road tunnel types. Additionally the influence of different fire loads and fire durations on the bearing capacity of the structures have been investigate existing tunnels regarding structural fire protection. The research results have also been the basis for a current update of national standards for tunnel construction.
Immediate user self-evacuation is crucial in case of fire in road tunnels. This study investigated the effects of information with or without additional virtual reality (VR) behavioural training on self-evacuation during a simulated emergency situation in a road tunnel. Forty-three participants were randomly assigned to three groups with accumulating preventive training: The control group only filled in questionnaires, the informed group additionally read an information brochure on tunnel safety, and the VR training group received an additional behavioural training in a VR tunnel scenario. One week later, during the test session, all participants conducted a drive through a real road tunnel in which they were confronted with a collision of two vehicles and intense smoke. The informed and the behaviourally trained participants evacuated themselves more reliably from the tunnel than participants of the control group. Trained participants showed better and faster behavioural responses than informed only participants. Interestingly, the few participants in the control group who reacted adequately to the scenario were all female. A 1 year follow-up online questionnaire showed a decrease of safety knowledge, but still the trained group had somewhat more safety relevant knowledge than the two other groups. Information and especially VR behavioural training both seem promising to foster adequate self-evacuation during crisis situations in tunnels, although long term beneficial behavioural effects have to be demonstrated. Measures aiming to improve users/ behaviour should take individual difference such as gender into account.
This article reports on a two-year study (2006 to 2008) of the distribution of de-icing salts (NaCl) applied to the road and the influence of traffic on the effective times of the de-icing salts. The research was focused on the needed resting periods of de-icing salts on road surfaces. The study used sensors installed in two lanes of the Motorway A4 in the area of the Dresden-Hellerau Highway Surveillance Center (Germany), to measure air and ground temperatures, wind speed and direction, liquid film thicknesses and residual quantities of salt on the road surface during ongoing traffic at 5-minute intervals. The authors conclude with four observations that can be useful for applying de-icing salts more judiciously: preventive spreading is only sensible if applied timely, i.e. immediately prior to icing events to be expected; the time-frame for preventive spreading on the dry road surface is maximum 60 minutes and on the moist road surface maximum 120 minutes; by increasing spreading densities in preventive spreading, this timeframe cannot be extended; it is completely sufficient if the spreading width is adjusted in such a way that the outer wheel tracks are also covered by the spreading. Distribution across the entire width of the lane will be caused by the rolling traffic within a few minutes.
The technology involved in traffic control in Germany has undergone significant changes. This paper describes how a group of German manufacturers have worked with operators to produce Open Communications Interface for Road Traffic Control Systems (OCIT). At the beginning of 2010, twenty-one different European manufacturers had bought licences for OCIT outstations.
The Joint Transport Research Centre of the Organisation for Economic Co-operation and Development and the International Transport Forum recently conducted a benchmarking study of the safety and productivity of typical highway transport trucks from various countries. This paper focuses on vehicle productivity and efficiency in regard to the movement of freight. Forty vehicles from 10 countries were examined. The vehicles were designed for longer-haul applications and were classified in three separate categories: workhorse vehicles, which are the most common and can travel on most roads; high-capacity vehicles, which may be restricted to a certain class of road; and very high-capacity vehicles, which may be restricted to specific highways or routes. The metrics used in the analysis include maximum cargo mass and volume capacity, optimum cargo density, fuel consumption, and carbon dioxide output as a function of the freight task. The study found that size and weight regulations have a significant effect on the productivity and efficiency of heavy vehicles, including fuel consumption and vehicle emissions per unit of cargo transported. Significant variations were found among the vehicles from participating countries as well as within vehicle classes. It was also apparent that, in general, higher-productivity vehicles are correlated more strongly with increased cargo volume than with increased cargo mass and that larger trucks are better suited to lower-density freight than are workhorse vehicles. The study also found that it is important to consider the freight task when evaluating vehicle fuel consumption and emissions.
This article describes the development of techniques to minimize automobile driver distraction when an in-vehicle information systems (IVIS) that requires visual attention is in use. The authors explain the visual occlusion technique that has been developed as a tool for the assessment of the in-vehicle human-machine interface (HMI) of IVIS in terms of visual demands. The authors addressed an unresolved issue in previous standardized experimental protocols - how subjects make use of the occluded intervals and how this might affect the assessments of visual demands. This study protocol assumed that subjects would continue task performance during occluded periods, leading to an underestimation of visual demands by the occlusion parameters "total shutter open time" (TSOT) and the "occlusion index". The authors predicted that a simple additional loading task to be performed in parallel could disrupt IVIS task performance during the occluded period leading to higher estimations of visual demands by TSOT and R. Their prediction was confirmed by the study findings. The results also showed that under the condition of additional auditory tracking, TSOT and R discriminated more clearly between an "easy" and a "difficult" IVIS task than under the standard condition. They conclude with a discussion of the implications of this research for designers of assessment tools for driver visual distractions.
Although many German monitoring sites report declines of NOx concentrations, NO2-concentrations actually stagnate or even increase quite often. Various analyses have identified the altered compositions of nitrogen oxides (NO2/NOx-ratio) emitted by motor vehicles (resulting in an increase of primary NO2-emissions) as well as the chemical environmental conditions (mainly ground level ozone) as the main causes. The chemical conversion of NO to NO2 is often parameterized in dispersion calculations of exhaust emissions. A widely applied conversion model is the so-called Romberg approach from 1996. However, the Romberg approach has to be re-evaluated to accommodate the above-mentioned conditions. This article presents an adjustment to the Romberg approach in accordance with the measured data from 2000 to 2006, taking into consideration substantially higher NO2/NOx-ratios especially for higher NOx-concentrations. Model calculations with OSPM (Operational Street Pollution Model) including its internal chemistry module are able to reproduce very well the trends in the measured annual NO2-concentrations over a 10 year period. The relevant parameters for variations between the years are the NOx-emissions, primary NO2-emissions, ozone concentrations, wind conditions, and background concentrations. A simplified chemistry model based on annual mean NOx- and NO2-concentrations, and background ozone concentrations, as well as primary NO2-emissions is presented as a better method than the updated Romberg approach. This model simulates the annual mean NO2-concentrations much more accurately than the conventional and the updated Romberg approaches.