1.2 Scope of this Part
The Austroads Guide to Road Design provides the designer with a framework that is intended to promote efficiency in design, construction and maintenance of a length of roadway. Part 3 is concerned primarily with the horizontal and vertical geometric design, along with the cross‑section standards that are appropriate for the functional class of the road. Part 3 also provides information relating to cycling, public transport and parking facilities as they apply in an on-road situation. Reference should be made to Guide to Road Design Part 6A: Pedestrian and Cyclist Paths (Austroads 2009a) for information regarding off‑road facilities for cyclists and Part 6B: Roadside Environment (Austroads 2015b). Designers should also consult Guide to Road Design Part 4: Intersections and Crossings – General (Austroads 2009b) for information about the appropriate placement and design of all forms of intersections, interchanges and railway level crossings.
This guide must be applied sensibly and flexibly in conjunction with the skill and judgement of the designer. The designer should have regard for the particular circumstances in each case, including the importance of the road, the nature and amount of traffic expected to use it now and in the future, and the cost and implications of alternatives.
Compliance with these guidelines does not relieve designers of the responsibility for establishing that their design is suitable, appropriate and adequate for the purpose stated in the project requirements. In selecting design criteria based on the guidelines, the designer should take care to ensure that the selection of minimum criteria does not lead to an unsatisfactory or unsafe design overall.
Design values that are not within the limits recommended by this guide do not necessarily result in unacceptable designs and values that are within those limits do not necessarily guarantee an acceptable design. In assessing the quality of a design, it is not appropriate to simply consider a checklist of recommended limits. The design has to be developed with sound, professional judgement and guidelines assist the designer in making those judgements. In general, minimum standards should only be used where they are considered necessary to meet one or more of the design objectives listed in Section 1.4. Generally, if a minimum is used for any particular design element, it is preferable to avoid using a minimum for another element in the same location so that the road is able to still provide an appropriate factor of safety to the road user.