REVIEW OF THE DESIGN SPEED CONCEPT

Historical development of the design speed concept and its current application by Australian road authorities are briefly reviewed. Criticisms of the concept and its application to alignment design are examined in the light of research findings and revised road authority practices. It is concluded that, while there appears to be no ready-made replacement for the design speed concept, deficiencies exist in its application to alignment design, particularly for the low and intermediate range of design speed values. Possible improvements to the traditional interpretation and applications of the concept are recommended. (A) /TRRL/