Evaluation of legibility of not properly reflecting signs

in conditions of dew or temperatures below 0 degrees C the reflection of reflecting material on signs can be suboptimal. Problems with respect to legibility under such conditions were studied, as well as subjective ratings of the signed information. Images of the signs were presented using an LCD projector. Independent variables in the experiment were age, amount of information, stimulus quality, and presentation time. Dependent variables were errors in reproduction of the names of the cities, towns or villages on the signs, and subjective ratings. It turned out that all factors both separately and additively affected the amount of errors. Positive subjective ratings coincided mainly with level of reflection, and to a lesser degree with the amount of information, presentation time and familiarity of information. Relevance to industry: Different types of reflecting material have been developed to reflect light from signs optimally. Disadvantage of some of the materials is the effect dew and temperatures below 0 degrees C can have on reflection and legibility. The study has practical consequences in terms of novelty and amount of information to be presented on such a sign. (c) 2005 Elsevier B.V. All rights reserved

The influence of alcohol (0.5‰) on the control and manoeuvring level of driving behaviour, finding measures to assess driving impairment:A simulator study

Objective: The influence of psychoactive substances on driving performance and traffic safety has been extensively studied. Research on the influence of alcohol at the control level of behaviour (i.e. automated processes) has been well established and has shown that the ability to operate a vehicle decreases with rising alcohol levels. However, results one level higher at the manoeuvring level (i.e. conscious processes), are inconsistent. The current study aimed to replicate findings on the influence of alcohol on the control level of behaviour and investigate effects on the manoeuvring level in order to find suitable measures to assess driving impairment. Method: The study was double-blind, placebo-controlled with a counterbalanced treatment order and a two-way crossover design. Thirty participants performed tasks in a driving simulator under the influence of alcohol (0.5‰) and a placebo. In the driving tasks the control level of behaviour (swerving, average speed, and speed variation) was investigated, as well as the manoeuvring level of behaviour (distance to other traffic during an overtaking manoeuvre, reaction time to a traffic light turning amber, and response to a suddenly merging car). Results: As expected, alcohol affected the control level of behaviour negatively. Participants swerved more and showed more speed variation after alcohol intake. The manoeuvring level of driving behaviour was also affected by alcohol. The distance to other drivers during an overtaking manoeuvre was smaller under the influence of alcohol. Results on reaction time were however less straightforward. Reaction time increased significantly under the influence of alcohol when reacting to a traffic light but not in reaction to a car unexpectedly merging into traffic. When analysing behaviour in reaction to these different events in more detail it became clear that they were responded to in varying manners, making it difficult to find an average impairment measure. Conclusions: The deteriorating effect of alcohol at the control level of driving behaviour was replicated, confirming the suitability of the standard deviation of lateral position and the variation in speed as measures of impairment. At the manoeuvring level, the kept distance to the leading car during an overtaking manoeuvre appeared to be a suitable measure to assess impairment as well as reaction time to a traffic light. The current study also confirms the difficulties in evaluating complex driving behaviour and the need for more research on this subject

An Ontological Approach to Inform HMI Designs for Minimizing Driver Distractions with ADAS

ADAS (Advanced Driver Assistance Systems) are in-vehicle systems designed to enhance driving safety and efficiency as well as comfort for drivers in the driving process. Recent studies have noticed that when Human Machine Interface (HMI) is not designed properly, an ADAS can cause distraction which would affect its usage and even lead to safety issues. Current understanding of these issues is limited to the context-dependent nature of such systems. This paper reports the development of a holistic conceptualisation of how drivers interact with ADAS and how such interaction could lead to potential distraction. This is done taking an ontological approach to contextualise the potential distraction, driving tasks and user interactions centred on the use of ADAS. Example scenarios are also given to demonstrate how the developed ontology can be used to deduce rules for identifying distraction from ADAS and informing future designs

Acute and subchronic effects of the H1-histamine receptor antagonist ebastine in 10, 20 and 30 mg dose, and triprolidine 10 mg on car driving performance.

1. The effects of a new antihistamine, ebastine (10, 20 and 30 mg), on several parameters of driving performance in actual traffic were studied in 15 healthy male volunteers. Subjects were treated for 5 days, and their driving performance tested on day 1 and day 5. The study was double-blind, placebo controlled and included the antihistamine triprolidine (10 mg sustained release) as an active drug control. 2. General tolerability was good except in one case following the reference compound triprolidine. No significant changes in driving performance were found with the new antihistamine ebastine at any dosage, on day 1 or day 5. Triprolidine (10 mg) significantly increased both the amount of weaving and the delay in following speed manoeuvres of a leading car, compared with placebo. 3. The results suggest that ebastine in doses up to 30 mg may be relatively safe for use by those who drive motor vehicles while under medication. The results do not warrant such a conclusion for triprolidine 10 mg

Criteria for driver impairment

Most traffic accidents can be attributed to driver impairment, e.g. inattention, fatigue, intoxication, etc. It is now technically feasible to monitor and diagnose driver behaviour with respect to impairment with the aid of a limited number of in-vehicle sensors. However, a valid framework for the evaluation of driver impairment is still lacking. To provide an acceptable definition of driver impairment, a method to assess absolute and relative criteria was proposed to fulfil the paradoxical goal of defining impaired driving which is consistent yet adaptable to interindividual differences