The focus on sustainability in urban development, policy implementation gaps and the role of public planner as ‘market actor’ have led to this research where we study how the implementation gap between sustainable urban policies and sustainable urban development projects can be bridged with the four planning tools of Adams et al. (2005). By conducting two in-depth case studies with different sizes of implementation gaps, we have looked at the planning tools in practice. The case of RijswijkBuiten had a small implementation gap and many planning tools have been used. In the case of Bruisend Dorpshart Kaatsheuvel the implementation gap was rather large and planning tools have been used to a lesser extent. Human capital supports capacity building, which in turn facilitates the other three planning tools: shaping, regulating and stimulating.