Human mobility shapes how urban policy effects spread across cities
This study evaluates three transportation interventions in Boston and New York City using both traditional geographic distance and mobility-network exposure, leveraging large-scale mobility data. In Boston, a free-fare transit program was found to increase overall activity by roughly 16%, particularly in lower-income areas, while Open Streets programs boosted visits to local food businesses. For Manhattan's congestion pricing, a mobility-based analysis revealed no net reduction in activity but a shift away from shopping and grocery trips, contrasting with geographic models that incorrectly predicted a general decline.
Why it matters — It demonstrates that evaluating urban policies based on spatial proximity rather than actual human mobility networks systematically distorts or misses their behavioral impacts. By analyzing 138 metropolitan areas across eight countries, the study establishes that geographic and mobility distances diverge locally in every city, proving that mobility-based exposure is a universally necessary framework for policy evaluation.