Coverage analysis
What 30 minutes covers in San Jose.
Bay-bounded and mountain-walled, San Jose isochrones are wide open along US-101 north and south but collapse sharply against the bay marshes to the north and the Santa Cruz Mountains to the west.
At 30 minutes, the San Jose isochrone captures the regional catchment — a zone where trips are planned but customers are willing to cross neighborhood boundaries. Unlike a 100–350 km² circle, the real road-network polygon follows San Jose's actual highway corridors, accounts for bridge and interchange chokepoints, and respects the natural and built barriers that force drivers to detour.
Best-fit categories at 30 minutes: Big-box, regional dining, car dealership, furniture, healthcare anchor, sporting goods. The 30-minute isochrone is the standard input for cannibalization studies and multi-unit expansion modeling.
The city-level population of 1,013,240 and a median household income of $117,000 give a sense of San Jose's economic density, but the figure that matters for site selection is the population inside the polygon — not the city as a whole. That number shifts dramatically depending on whether you're drawing from a high-density urban core or a lower-density suburban corridor. Use the tool above to set your actual candidate location, then generate the isochrone to see the real catchment.