A significant number of car accidents is attributed to the slipperiness of the road (e.g. because of rain or ice), to unexpected problems in the road conditions (such as an accident or landslips), as well as to carelessness of the drivers. It is often observed that drivers ignore the warning signs on the sides of the roads, since the information they provide is mostly outdated and therefore unreliable (warning signs are typically permanently placed on a spot and their content cannot easily be updated). Furthermore, a driver cannot be informed of the intentions or the state of a vehicle ahead (for example the intention to change lane or a sudden abrupt braking). As a result, the driver cannot be prepared on-time to handle a potentially dangerous situation. This becomes even more important in highways or high-speed motorways, where the time margins of reaction are limited.

On a different level, traffic congestion and air pollution constitute two of the greatest problems in the daily life of residents of urban areas worldwide, to the extent that they are considered even more serious life-threats than violence and crime. Traffic congestion is the main reason for wasted time and fuel consumption during driving inside the urban limits. Besides the waste in energy resources, this results in significant air pollution, which increases to an alarming degree the number of citizens suffering from chronic diseases. Although, these two problems (traffic congestion and air pollution) are directly interlinked, for decades they have been treated separately or at best, with a relaxed correlation.

EXEHON project is aiming at developing a single system that will work against the two problems identified:

- On a first level, EXEHON informs a driver about problems of the surface of the fore coming part of the road, as well as of the probable intentions of the leading drivers. The system will rely on the deployment of sensors installed on vehicles and the road network and a wireless communication network which will allow information exchange between adjacent vehicles and vehicles and base-stations.

- On a second level, the proposed project is expected to set the technological infrastructure upon which a unified environmental solution to urban traffic and air pollution control can be developed. EXEHON project proposes the use of fixed base-stations that can be integrated on traffic lights within the urban limits. This way, a number of applications can be developed to intelligently control the flow of vehicles through the traffic lights in order to enforce different environmental policies.