Road Design

The purpose of this report is to review batter slope guidance in the Austroads Guide to Road Design (AGRD) and identify opportunities for improvement and harmonisation. It presents the findings of Workstream 1.3 of Austroads project SRD6407, which addresses gaps and inconsistencies in existing road design guidance.

A literature review covered Austroads guidance, jurisdictional supplements from Australia and New Zealand, relevant research reports, and selected international references. The review examined how batter slopes are selected and applied in different design contexts.

The review found inconsistencies in terminology, recommended batter slopes and design principles across AGRD Parts 3 and 6 and jurisdictional supplements. The review also identified different approaches to balancing motorist safety, slope stability, maintenance requirements, landscaping objectives and erosion control.

The report recommends a more consistent and holistic approach to batter slope selection. Future guidance should consider safety, stability, maintenance and environmental outcomes together, rather than focusing primarily on slope stability. The findings support guidance updates across AGRD Parts 3, 4A and 6 made in 2026.