Landscape Optimization of Expressway Cutting Slope Considering Driver Safety and Visual Characteristics

To improve the landscape and safety value of expressway cutting slope, an optimization idea of cutting slope landscape considering driver safety and visual characteristics is proposed. First, combined with the dynamic visual characteristics of drivers, the improved driving sight distance, focal point and farthest field of vision were taken as parameters. The visual sensitivity of the expressway was divided into zones; and the spatial range of high, medium, and low levels of visual sensitivity was obtained. Second, combined with the clear zone design specifications, the clear zone setting of the cutting slope with a slope of 1: 8 - 1: 0. 75 in six groups of slope heights and the simulation test of the landscape proportion of the visual sensitive zone was carried out; and the threshold of the landscape proportion of the cutting slope in the high visual sensitive zone after meeting the clear zone design specifications was obtained. Finally, combined with the test results, the optimization suggestions of the cutting slope were submitted to maximize the landscape influence on improved driving safety. The results showed that when the speed is 80 km • h_1, the high visual sensitive zone is 37 m wide and 10 m high, and the average width and height of the medium and low visual sensitive zones arc 119 m and 82 m, respectively. When the slope height is 0. 75 m, the landscape proportion of 1: 8 - 1: 7 slope exceeds 50%. Further, when the slope height is greater than 3 m, the landscape proportion of the cutting slope is less than 1*1. 5 > occupying the highly sensitive zone that reached a fixed value of 71%. When the slope height is fixed, the more gentle the cutting slope, the easier it is to meet the requirements of the clear zone width setting; this facilitates the enhancement of the traffic safety attribute and increases the proportion of the slope landscape. © 2022 Xi'an Highway University. All rights reserved.