Zell-Ziegler, Thema and Dünzen operationalise sufficiency by translating it into causal policy chains rather than treating it as a general ethical preference. The paper adopts the IPCC definition of sufficiency as measures and daily practices that avoid demand for energy, materials, land and water while delivering wellbeing within planetary boundaries. Its distinctive methodological contribution is the impact-chain framework, which traces the path from policy stimulus to behavioural, infrastructural and environmental effects while identifying supporting factors, barriers and risks. Seventy-four passenger-transport policies are examined across multiple strategies, including trip reduction, active mobility and modal shift. The analysis is valuable because it refuses to equate a low-demand intention with successful implementation: feasibility depends on administrative flexibility, public transport provision, distributional effects and political acceptance. The paper thus connects sufficiency research to policy design and implementation studies. More broadly, it turns “less” from a moral slogan into an analysable institutional mechanism whose consequences can be compared, qualified and tested.