This literature review is primarily aimed at describing studies that deal with the interaction between driver behaviour and variable message signs, VMS. The collected references are, for the most part, published in Europe or studies about European conditions, published during the years of 2000-2005. Areas treated in the study are effects on driver behaviour, driver attitudes, design, understanding and recall of VMS, and accidents and regulations concerning VMS. The literature review is supplemented by a behavioural background and recommendations from a behavioural science perspective.

Sharp curves constitute a significant safety risk. The question is if it is possible to design sharp curves in such a way that drivers pass them with greater safety margins? In this work we studied the effect of transition curves (in the form of clothoides) added to the constant radius curve segment on drivers´ choice of speed and maximal lateral acceleration. The study was carried out in VTI´s driving simulator II. Influence on the results of the subjects´ experience and training in driving the simulator was studied by repetition of the first experimental session for all subjects on each of the following two working days. The results showed, firstly, that the drivers chose higher speeds in curves with clothoides, secondly, that there was no difference in maximal lateral acceleration, and finally, that these results were not influenced by training.

Car drivers' spontaneous speed choice in urban areas was studied and compared with posted speed limits. Two groups of middle-aged men, experienced car drivers, participated in the study. One group consisted of thirteen drivers with at least five years experience of car driving in Linköping. The other group consisted of eight drivers with very little experience of car driving in Linköping. The participants drove a pre-determined test route in the city of Linköping four times with covered speedometer. The total driving distance was 96 km. The participants were alone in the car during driving. Route guidance was given during the drive, both verbally and visually. The location and timing of the guidance were controlled by a GPS-based computer. Before the test drive the participants were instructed to drive as they normally do without stress. The participants' speed (75th percentile) for each of the route sections and for each of the four drives was measured and analysed. After completion of the test the participants rated some of the route sections. The measured speed varied substantially between route sections (traffic environments). However, the agreement between measured speeds across route sections was large between as well as within individuals. Along some route sections the speed was higher, and along others it was lower, than the posted speed limit. The speed variation across traffic environments (route sections) can to a large extent be explained by the variation between the traffic environments and to a much less extent by the variation between participants.

Sharp curves constitute a significant safety risk. The question is if it is possible to design sharp curves in such a way that drivers pass them with greater safety margins? In this work we studied if the drivers´ choice of speed and side acceleration will change with the location of the centre of rotation for banking of sharp curves. Influence of training was studied by repetition of the first experimental session during each of the following three working days for all subjects. The study was carried out in VTI´s driving simulator (Model I). The results show firstly, that the location of the centre of rotation for banking of sharp curves influenced the drivers´ choice of speed and side acceleration and secondly, that these results were not influenced by training.

The report begins with a short description of the state of knowledge at present, and of the age-related functional impairments that affect car driving. Two explanatory models are described as to why accidents occur. After that, there is a discussion of what general principles should apply to simplify the task of driving. The main part of the report consists of a run-through of the research literature, focusing on the ability of older car drivers to observe and familiarise themselves in traffic. In that respect, results and conclusions/recommendations have been presented as regards how road junctions and roads should be designed, and how the design and location of signs, traffic signals and road markings should be executed in order that the requirements of older people may be satisfied. Because only the external traffic environment has been dealt with in this study, such things as vehicle design or intelligent transport systems (ITS) solutions in the vehicle itself are not discussed. In the concluding chapter, some design principles for roads and elements of the road environment are given, which can be read independently as the principles apply to all car drivers.

This literature review aims to survey Swedish and foreign design solutions to meet mainly speed and accessibility requirements of roundabouts and to see if foreign experiences are relevant for Swedish conditions. Great importance has also been given to studying to what extent there are "functional categories" of roundabouts. The survey shows that lower speed and single lane in roundabouts improve traffic safety. Furthermore that there are good possibilities to control speed through design e.g. using narrow, radial entries and exits with small entry radius, entry and exit deflection to the left, design for an entry path curvature with small radius and traffic island. The survey also shows that give way regulations between vulnerable road users and motor vehicles in Sweden can be made clearer. The idea of dividing roundabouts and the entire traffic system into distinct "functional categories" is to improve traffic safety by decreasing the risk of the road user to misunderstand the situation. To create good categories of roundabouts it ought to be investigated what is needed and how it can be mediated to the road user what function category roundabout he is in. Several countries have, just as Sweden, a not very pronounced category classification of roundabouts.

Projektet genomförs i nordisk samverken inom NMF (NordiskMörkertrafikForskning). Alla reflex-folier för vägmärken, som fanns på den nordiska marknaden 1997, har monterats på identiskt lika provskyltar som exponeras för trafik utefter landsväg på 9 provplatser:

• Damnark 2
• Finland 2
• Island 1
• Norge 2
• Sverige 2.

Provplatserna är valda så att de täcker in en stor klimatvariation. Efter "nymätning" vid utsättningen av provskyltarna 1997 görs mätning av retroreflexionen hos de rengjorda folierna under sensommaren varje år. Dessa mätningar har under år 2000 kompletterats med färgmätningar på ett antal provskyltar. I rapporten redovisas resultaten efter 3 års exponering. Projektet fortsätter.