It is neither safe nor realistic to let a broken down or exhausted vehicle cross several lanes and park on the right shoulder. According to experience, a hard shoulder of at least 2.5m should be set on the left side for anchored vehicles to stop or wait for traction.
When separated sections are adopted in expressway and Class I highways, the left hard shoulder should be set. The edge of the lane within the width of the left and right hard shoulders should also be provided with side strips, the width of which is generally 0.75m or 0.50m m. ..
Extended data:
Starting from the top of the longitudinal slope, oblique openings with a width of 300~500mm are staggered to both sides at intervals of about 20000mm, and they are filled with gravel or crushed stone. At the same time, a water retaining sill with a height of 100mm, an upper width of 100mm and a lower width of 200mm is set at the edge of the shoulder. At each cut-off open channel, there is a spout, and the slope under it is reinforced with turf or masonry, so that the water flows out from the channel in a concentrated way.
When the waterfall rains, the maintenance personnel can temporarily set up a water retaining dike at the lower side of the open channel along the shoulder to force the rainwater to be discharged from the grass, but it should be removed immediately after the rain. Grass naturally growing on the shoulders of middle and low-grade roads should also be retained. Sod should be planted with seeds suitable for local soil. After survival, it should be maintained and trimmed so that the height of grass does not exceed150 mm. If there are overgrown weeds, it should be removed and resurfaced to keep the pavement beautiful.
If there is too much sand deposition in the shoulder grass that hinders drainage, it should be removed immediately to restore the proper cross slope of the shoulder. When using herbicides to remove weeds, we should pay attention to the impact on the environment along the line. Outside the shoulder, the gap is most likely to be trampled by livestock washed away by the flood. You can use stones, cement concrete precast or turf to lay shoulder pads with a width of about 200mm, which can not only eliminate diseases, but also beautify the road capacity.
Baidu encyclopedia-Shoulder