Study on the D/h Ratio of City Road’s Environmental Effect Based on Bim

Based on urban planning theory, the paper conducts a study on the D/H ratio of city road and applies a new technology BIM to make a quantitative objective analysis on the space size of road, differing from traditional subjective evaluation from the perspectives like psychology, physiology, social behavior and urban esthetics. Through the simulation and analysis on sunshine, ventilation under different D/H ratio, this paper discusses relationship among D/H, sunshine and ventilation and the change rule of sunshine and ventilation based on different D/H value, thus to get the best value range of D/H at planning level, and to demonstrate the traditional suggested value to sum up optimum value of D/H with more sufficient grounds. A new urban planning method is also involved in this paper.