Understanding New York's geography
Why New York's drive times defy radius math.
Manhattan's grid is fast on paper and crawlingly slow in practice, while the outer boroughs and New Jersey suburbs depend entirely on a handful of bridges and tunnels — the Lincoln, Holland, GW, Verrazzano, and the East River crossings — that turn every drive-time polygon into a time-of-day question. A 30-minute isochrone from Midtown can reach Newark midday and barely cross the Hudson at 5pm. The MTA and PATH networks also mean drive-time may understate true reach: a transit-time isochrone often shows a meaningfully different trade area, especially in Brooklyn and Queens.
Retail real-estate teams working New York should run both drive-time and transit-time isochrones in parallel, then take the union for residential reach and the intersection for daytime population. Franchise concepts that depend on car-based trips (auto services, big-box, suburban QSR) should focus on Long Island, northern New Jersey, and Westchester where drive-time behaves more conventionally. Brooklyn and Queens neighborhood retail is better modeled on 10-minute walk + subway-stop catchments rather than driving radii.