The Austroads Guide to Road Design is the NZ Transport Agency's primary source of guidance for the design of the highway network. However, there are some important New Zealand specific variations and interpretations that reflect our unique terrain, driving conditions and road rules.
Technical memorandum TM2501 Superelevation calculations, provides information for practitioners on the calculation of road superelevation appropriate for a vehicle speed and curve radius. This is consistent with the SHGDM chapter 2: basic criteria.
This information should be used in place of that given in the Austroads Guide to Road Design Part 3 Section 7.7.1.
Technical Memorandum TM2502 Preferred method for calculating road surface water run-off in New Zealand, provides advice on the preferred method of calculating surface water flow and the limited use of the Gallaway method in New Zealand.
This update highlights an error in the formula on page 3 of the original document Highway surface drainage: A design guide for highways with a positive collection system and quotes the correct formula.
The primary source of design guidelines for the State Highway Network is the Austroads Guide to Road Design 2009. However, the State highway geometric design manual (2000) may be an important reference document for some projects, depending on their context and the stage in their life-cycle.
The launches of the Safer Journey's initiative and the Decade of Action for Road Safety(external link) have brought the way we design for safety into the limelight. Technical Memorandum TM-2503, Guidelines for edge protection and medians on dual carriageway roads, incorporating a Safe System philosophy, defines the interpretation of a Safe System philosophy for dual carriageways, including the RoNS projects and how this may vary with context.
Appendices to this memorandum provide examples of the rationale in practice, an analysis of the benefits and costs and also typical sections that illustrate these principles.