Road Design

The Guide to Road Design – Part 4B: Roundabouts provides road designers and other practitioners with guidance on the geometric design of roundabouts. However, the guide generally contains only advice that is specific to the design of roundabouts and should therefore be used in conjunction with three other parts of the Guide to Road Design that relate to the design of intersections, namely: Part 4, Part 4A, and Part 4C. Part 4B covers design principles and procedure, and provides guidelines for all the key elements thus enabling practitioners to develop safe and efficient layouts. It also provides information on pedestrian and cyclist treatments at roundabouts and related topics such as pavement markings, signs, and landscaping. It also includes a new design method for roundabouts that focuses on the entry curvature to achieve a reduction in vehicle approach speeds rather than applying the ‘deflection method’ used in previous Australian guides. This second edition contains updates to address concerns regarding bicycle lanes approaching and while on roundabouts.