Research progress on vegetation restoration of road slopes in China

China is the largest country in road construction due to rapid economy growth, which results in a large number of exposed slopes. Vegetation restoration of these road slopes has become the dominant method in ecological restoration. We reviewed research progress from three aspects, including key technologies for road slope vegetation restoration, application of vegetation restoration engineering, and factors influencing the vegetation restoration efforts. The slope protection technologies commonly used in road slope vegetation restoration include soil spraying technology, vegetation concrete slope protection technology, thick base material technology, and hydraulic spraying technology. In engineering applications, slope vegetation has the functions such as soil and water conservation, air purification, and landscape restoration. Currently, the most common community configuration is shrub and grass configuration. The main influencing factors of vegetation restoration on road slopes are climate, soil substrate, slope direction, plant species and community configuration used, human factors, and other natural factors (such as hydrology, altitude, microtopography, and wildlife). Future researches should focus on the mechanisms of different factors affecting road slope vegetation restoration, and study ecological substrates and slope protection technologies, plant species and diverse community configuration models suitable for road slope restoration in different climatic regions and site conditions.