A night-time road visibility index for the diagnosis of rural road networks
Road visibility is used as a performance index by both road lighting and automobile lighting engineers. We propose a road network visibility index devoted to road operators, in order to assess the quality of their inter-urban networks in terms of night-time visibility. On rural roads at night (without public lighting), an object on the road is only visible to the driver if it is illuminated by the headlights. Its visibility depends on its geometric and photometric properties, on the photometric properties of the headlamps, and on the retro-reflection properties of the road in the background. Our goal is to compute a visibility level index along a road itinerary, to serve as a tool of diagnosis for road operators who may want to know where on their network the night-time visibility is poor. This tool may also assess the improvement brought by modifications of the infrastructure. We use an instrumented vehicle (Ecodyn), calibrated it in order to measure the retro-reflection of the road pavement. We get a profile of the retro-reflectivity along the road, then we consider average headlamp photometric data (UMTRI European low-beam), and compute the profile of the visibility level, as indicated in Adrians model, for a given target along the road. This methodology was tested on two itineraries of several kilometers. As a conclusion, we propose a night-time road visibility index for roads without street lighting, and show the feasibility of the measurement with an existing photometric system. This methodology is mainly dedicated to road operators, but may also find applications in the conception of advanced front-lighting systems through the in-vehicle use of visibility level digital maps of road networks.
night driving road visibility quality index road diagnosis onboard equipment.
Roland BREMOND Hicham CHOUKOUR Yannick GUILLARD
Laboratoire Central des Ponts et Chaussées, Paris, France Laboratoire Régional des Ponts et Chaussées, Strasbourg, France
国际会议
26th Session of the CIE(国际照明委员会（CIE）第26届大会)
北京
英文
796-799
2007-07-04（万方平台首次上网日期，不代表论文的发表时间）