Background: Unhealthy food and drink advertising influences societal food norms, nutrition knowledge, food preferences, and contributes to poor dietary intake. In July 2025, the Government of South Australia restricted the advertising of unhealthy food and drink on government-owned public transit assets (buses, trams and trains). This study evaluates the impact of the policy on exposure to unhealthy food and drink advertising on government-owned transit assets and examines two unintended outcomes: substitution toward permitted master branding advertisements, and displacement of unhealthy food and drink advertising onto assets not covered by the policy.
Method: Prior to policy implementation (June 2025), a baseline environmental scan was conducted to capture advertisements across metropolitan Adelaide public transit assets (buses and trams) and related stationary infrastructure assets (stops/shelters, stations, billboards, and phone boxes). Food and drink advertisements were classified as permitted or restricted as per the policy implementation guidelines. The environmental scan was repeated one year post policy implementation (June-July 2026). Data collection was expanded to capture a greater number of government-owned stationary assets not included in the 2025 baseline to enable subgroup analysis by asset ownership.
Results: Pre-policy, around two-thirds of food and drink advertisements on government owned buses and stationary assets were classified as restricted. Final results, including pre-post comparisons and subgroup analyses by asset type (mobile and stationary) and ownership (government and non-government), will be available for presentation at the conference.
Conclusion: This evaluation will provide timely evidence on the real-world impact of restricting unhealthy food and drink advertising on public transit assets. This study is the first evaluation of such a policy in an Australian jurisdiction, and the findings will inform potential policy expansion in South Australia and nationally.