Study On Disability Glare Indicators Of Overpass Guardrail Lighting

This research is the the mid-section of the 2011 National Natural Science Foundation Project "Safety research of urban overpass lighting based on high-dynamic image technique"(project number: 51178299). Urban overpass plays an irreplaceable role in road traffic, with multi-direction, ease the traffic pressure, and ensure the characteristics of high speed transport. Compared with the general road, overpass has higher requirements on lighting safety. As the result of guardrail lighting does not need lamp post, low installation height and easy maintenance, and has a significant guiding role on the driver, it gradually began to use in the urban overpass. But at present, there is lack of relevant research on overpass road lighting disability glare evaluation index, the vehicle road lighting standards at home and abroad are also not clearly defined; there is also lack of the guardrail lighting related research and industry norms. Put forward the suitable threshold increment value for China’s urban overpass road guardrail lighting, which has great significance of avoiding disability glare and provides a good lighting environment for driver.In this paper, through the analysis of the causes of human visual fatigue, and combined with the guardrail lighting installation small spacing, proposed to control the spacing of the installation through controlling the scintillation effect. Combined with the definition of threshold increment, deduced angle formula of line of sight and the glare source center issued light.At the same time, based on the investigation of six guardrail lighting overpasses nationwide, the paper evaluates the present situation of guardrail lighting overpass in China, and summarizes the present problem is the lack of the guardrail lighting overpass standards and related research.Based on the problem of the investigation of the current situation, the paper started a preliminary research on the overpass guardrail lighting. First, we determine ten typical overpass models(include five single-lane model and five double-lane model) and the installation of lamps. Then we do the simulation for each model with DIALux. So we can get a range of values of installation height and space which are suitable for single lane and double lane. Threshold increment was calculated.Based on the threshold increment obtained, respectively, make the installation height, the installation distance, overpass slope as the independent variable, TI as the dependent variable, to analysis the variation rule of TI value. Through the analysis of variation of TI, predicted the distribution law of each interval of threshold increment, and put forward the appropriate threshold increment limit value.