Triple Access Planning (TAP) is the idea that accessibility can be delivered through physical mobility, digital connectivity, and spatial proximity. There is great uncertainty as to how far one of these three elements will substitute for or complement the others in delivering the accessibility we need in future. Sustainable Urban Mobility (SUM) Planning is touted as a relatively new paradigm in local transport planning oriented to the achievement of a wide range of societal objectives. The paper presents a review of how well SUM Plans from eight European countries, and national guidelines from four currently account for TAP and uncertainty in their approach. Our findings suggest that while the concept of physical proximity is well-understood, other aspects of the TAP and uncertainty approach are not. Digital connectivity is largely ignored. The planning future is treated as largely certain, with no consideration of disruptive factors that might alter this future.