🧪 Sustainable Cities Simulation

Sustainable urban planning is a three-way trade-off between how densely a city builds, how much land it keeps green, and how well it connects people to transit — push any one lever and the other two respond. This simulator renders a live 10×10 city block in 3D and lets you tune building density, green-space share and transit coverage independently, recomputing per-capita building energy, transport CO₂ and urban-heat-island intensity in real time from the same relationships urban-sustainability research actually uses: a power-law density discount on per-capita energy, the compact-city elasticity linking density and transit to vehicle-miles travelled, and a vegetation-cover mitigation term for heat-island intensity. A composite Sustainability Index shows where the three trade-offs genuinely balance, rather than where any single number looks best in isolation.