  Increasing urbanization puts pressure on cities to prioritize sustainable
growth and avoid carbon lock-in. Available modeling frameworks fall acutely of
guiding such pivotal decision-making at the local level. Financial incentives,
behavioral interventions, and mandates drive sustainable technology adoption,
while land-use zoning plays a critical role in carbon emissions from the built
environment. Researchers typically evaluate impacts of policies top down, on a
national scale, or else post-hoc on developments vis-\`a-vis different polices
in the past. Such analyses cannot forecast emission pathways for specific
cities, and hence cannot serve as input to local policymakers. Here, we present
IMPACT pathways, from a bottom-up model with residence level granularity, that
integrate technology adoption policies with zoning policies, climate change,
and grid decarbonization scenarios. With the city at the heart of our analysis,
we identify an emission premium for sprawling and show that adverse policy
combinations exist that can exhibit rebounding emissions over time.
