Evidence shows that many types of accidents appear in clusters, particularly in those 'black spots' where problems with road infrastructure exist. Some stretches of highway are notorious for making drivers feel drowsy or for causing them to make mistakes. Less well known, however, is that a road's physical properties can help in developing and improving on-board safety features such as antilock brakes and electronic stability programs. A European road safety engineering initiative set out to reduce the number of accidents on Europe's roads by identifying dangerous stretches of highway and recommending remedial actions. The 'Ranking for European road safety' (Rankers) project aimed to bridge the divide between European policy making and the operational needs of road engineers, network operators and road administrators. The consortium was coordinated by the Research and Development Centre in Transport and Energy (CIDAUT) based in Spain. It involved 17 organisations from 9 Member States which reflected the different areas of knowledge and expertise necessary for accomplishing the project's ambitious objectives. Prevention first Preventative measures were identified by researchers and ranked according to their cost-effectiveness. The results were used to develop a series of recommendations for ensuring that accident clusters don't occur. A road safety index was produced for monitoring and assessing road safety, as well as a catalogue of remedial measures that were ranked by efficiency. Both measures comprised a set of practical recommendations that can help pioneer a Europe-wide culture of safer highways. The Rankers project developed an interactive tool on the internet called the 'Rankers e-book', which can look for different countermeasures using key words. It may be used by road authorities and other users to solve a specific problem such as motorbikes crossing roundabouts, by providing specific countermeasures. The project's index is a technique for evaluating the safety of a particular section of road and is divided into six different topics. According to Guillermo Ramos, the project's scientific coordinator, these include road alignment, intersections and junctions, and the different aspects that act as cues to drivers overtaking on a single carriageway road. Other topics, he says, include an index for determining the probability of an accident depending how far the risk element, such as a tree or other hazards, is from the road. 'The condition of the road and the human factor, such as how drivers modify their behaviour according to the road layout, were also considered,' he adds. Since road infrastructure is believed to be involved in a third of all road accidents, safe road engineering supported by sound research can help ensure consistently high levels of safety along Europe's highways. Thanks to the scientifically-based guidelines developed by Rankers, highway authorities will be able to make better informed decisions. This will enable authorities to prioritise road infrastructure investment, leading to the eradication of the most hazardous stretches of road to give a safer road network. Existing information was used to find indicators of safety problems for the road safety index. These included data on traffic levels, accidents and road maintenance. Additional information concerned the quality and geometry of the road's surface and the roadside layout. The consortium also identified important indicators for studying trends in road safety, such as the need to stop accident black spots from developing. Until now, the usual practice has been to identify hazardous stretches of road by the number of fatal accidents. The Rankers project enabled authorities to be more proactive and anticipate the most dangerous parts of the road network without having to wait for deaths to occur. The human touch The three most important factors influencing road safety are the human being driving the vehicle, the vehicle itself and the infrastructure of the road on which it travels. Together they make up the 'three safety pillars', which reveal how the characteristics of a highway influence the likelihood of an accident occurring. Therefore, the relationship between these three factors was carefully considered. Highways of all different types, from motorways to country lanes, were analysed using state-of-the-art technology to gain fresh insight into how roads interact with drivers and their vehicles. Video recording equipment was fitted inside and outside an experimental vehicle to record how a driver's state of mind can be affected by a road's geometry. Researchers monitored driver performance, along with vehicle position and speed. Engineer José Miguel Perandones says that a driver's level of focus can be measured according to the amount of time taken to carry out an action, such as braking, turning or accelerating. 'The position of the car in the traffic lane is also important,' he says, 'because if you are confused you cannot maintain your position in the lane.' Experiments were conducted under actual driving conditions to determine the impact of 'behaviour setting' road infrastructure on drivers' behaviour. The project defined and developed two different types of experiments and undertook two different field tests. One test was used to analyse the road infrastructure and its interaction with the driver, mainly the influence of curvature radius, while the other examined how road signage affects drivers, the so-called human component. The belief was that a winding and uneven minor road would influence a driver's behaviour differently than a smooth, straight dual carriageway. One example, for instance, was how the curvature of the road affected the speed at which the driver drove the vehicle. At the same time, researchers investigated how recognition of road signs was affected by their design and location and how other roadside features influence drivers' awareness of their surroundings. 'Road signs can have an effect on drivers' expectations,' Mr Perandones explains. 'If there are too many signs, with too many different colours the driver will be unable to understand and lose concentration. You cannot deal with too much information at once.' Self-explaining roads? As the human component is involved in the majority of road accidents, it is very important that drivers get all the help they need to complete their journey without incident. Since the 1980s, researchers have studied how a road can provide drivers with valuable information, influencing both the way they drive and their interactions with other road users. This has led to the development of 'self-explaining roads', which assist the driver by revealing where the vehicle should be positioned; as a result, they are both easy to use and navigate. This approach acknowledges that the road environment can provide important information to help guide drivers and their interactions with fellow road users. This can be achieved by adopting the same design principles for all highways and taking into account the needs of different users. The Rankers project was co-funded by the 'Sustainable surface transport' initiative of the European Commission's Sixth Framework Programme. It sought to create safer roads by not only helping to lessen the effect of an accident, but to stop it from happening in the first place, boosting quality of life for EU citizens. The drive for safer roads in Europe doesn't end with the successful Rankers project. 'We have been approached by organisations based in the United States and other parts of the world who are very interested in our work,' concludes Mr Ramos.