Lighting as an aid to driving is all around us in the form of road lighting, vehicle lighting, road signs, and traffic signals. But all is not well with lighting as an aid to driving. The design principles of road lighting have changed little since the 1930s, yet vehicle lighting has changed out of all recognition. The contribution of vehicle lighting to visibility is rarely considered by the designers of road lighting, and the contribution of road lighting to visibility is rarely considered by the designers of vehicle lighting. The driver’s task has become more difficult as competition for attention has increased. Traffic densities are higher, traffic speeds are faster, sources of information relevant to the driver are more frequent, and sources of distraction are seldom absent. As if this were not enough, there is pressure on road lighting from people concerned with the collateral damage it causes by consuming electricity and by generating light pollution. Finally, the nexus of sensors, high levels of computer power in small packages, and wireless communication offers unheard-of flexibility for road lighting, vehicle lighting, signs, and signals. These possibilities, together with the limitations of current practice, make a review of the contribution of lighting to the safety of drivers and others on and near the road, timely. Such is the purpose of this book.