Abstract:Design speed is the most important technical standard of urban expressway, which determines the other technical standards and investment scale. Four principles of selecting the design speed of urban expressway are summarized from three aspects of influence factors, case analysis and specifications. The unified technical standards should be selected as far as possible for the same expressway. When the road sections with the different design speeds are connected to each other, the horizontal and vertical linear technical indicators before and after adjacent sections should coordinate and cooperate with each other and these indexes should change gradually. The obvious signs are set up at the changes and the demarcation points of design speed for sections are easily selected at the positions of interchange or access ramps. The design speed of Gannan Avenue expressway is selected according to the principles.
