Highway Landscape Planting Design Based On The Traffic Safety

A higher expect of road service level——a safer and more comfortable driving environment, was proposed along with the continuous increment of our highway mileage and improvement of national life level. As an important part of highway traffic environment, landscape greening has always been a hotspot of industry research, however, most of the highway landscaping designs in our country focus on the beautifying function, considering the role of security inadequate. Therefore, it is necessary to study highway landscape greening design systematically and comprehensively from the point of traffic safety.On the basis of summarizing correlative literature both in home and overseas and analyzing the relationship between highway traffic safety accidents and landscape greening in our country, this paper has studied highway landscape greening design from aspects of sight distance, anti-glare planting in central dividing strip and driver’s psychology and physiology based on the traffic safety requirements. On the basis of analyzing intersection sight distance requirement under different traffic organization, the control area of landscape greening was proposed, the related calculation model was established, the maximum height of shrub, the maximum stem diameter of tree, the minimum planting distance of tree, and the minimum height of tree branch in control area were put forward. On the basis of protecting the clear sight in the stopping sight distance range, the control area of central island ‘s landscape greening and the maximum height of plants in it were put forward by establishing and analyzing the computation geometry model. On the basis of defining the recognition distance of signs, and combined with drivers’ visual characteristics, the length of landscape greening control area in front of interchange exit was put forward. Applying the theory of vehicle decelerating and lane changing, safe sight distance in front of interchange entrance was calculated and analyzed, and combined with ramp safety stadia, the control area of landscape greening in front of interchange entrance was proposed. Based on the calculation model of lateral clear distance, and guaranteeing the sight distance, the control area of landscape greening on main line and central dividing strip curve was proposed. On the basis of analyzing the vehicle and driver’s visual characteristics in openings of central dividing strip and synthetic separation zone, the corresponding greening control area was put forward.Through the calculation model of anti-glare planting distance in central dividing strip, antidazzle planting distances of straight and curved sections’ different crown diameter plants in most unfavorable situation were put forward. On the basis of considering the factors of highway cross slope and plant’s crown diameter, and combined with road plane and vertical surface geometry parameter equation, the calculation models of straight, horizontal curve and vertical curve sections’ plant anti-dazzle height were built, and the recommended values of plant antidazzle height were put forward.Introducing the concept of iconic plant, and on the basis of analyzing the driver’s visual characteristic and reaction process, the control requirements of plant’s vertical layout, horizontal layout, height from top to road surface, type selection, arrangement form were put forward. Studying the relationship between exciting frequency and heart rate decline, reasonable length of humdrum greening period was proposed. Studying the discomfort light flicker frequency and visual transition model of tunnel entrances, the border trees distance and the length of tunnel entrances’ light reduction period were proposed. On the basis of considering the driver’s visual effect, the incomplete obscured ideas and obscured planting distance were put forward. Studying the relationship of color contrast and color psychology, the color selection and collocation of greening plants were put forward.