以甘肃省某高速公路隧道洞口为例，通过对几种不同洞门减光防眩构造物（遮光棚、遮阳棚、遮光板）的比较研究，指出遮光棚不仅可解决减光过渡的问题，还可达到防眩的效果；通过对2种不利工况的分析，得出20°入射角是导致驾驶员失能眩光的角度。提出了遮光棚设计应注意的事项，如拱肋间距、铝合金管环向间距、亮度等。

Taking the lightweakening and antiglare design of an expressway tunnel portal in Gansu, China as an example, the authors make the comparative analysis on the operational performance of different kinds of lightweakening structures at tunnel portal. The analysis results show that lightweakening shed can not only solve the problem in the transition section of lightweakening, but also has antiglare effects. Then, the authors, by analyzing on two adverse working condition, put forward that  20°angle of incidence is the angle that induces the glare of drivers, and the points to which attention should be paid for lightweakening shed design, such as arch ribs interval, circumferential spacing of aluminium alloy pipes and luminance.