Understanding Los Angeles's geography
Why Los Angeles's drive times defy radius math.
LA's freeway network (the 101, 405, 10, 110, 5, 134, 210) is the controlling variable for every isochrone, and the Santa Monica Mountains physically separate the Westside, the Valley, and the Eastside in ways that constrain reach to a handful of canyon passes. A site in Sherman Oaks looks great on a map relative to Beverly Hills until you realize the 405 over the Sepulveda Pass adds 25 minutes at peak. Coastal sites (Santa Monica, Manhattan Beach) have effectively half-moon trade areas because the Pacific erases the western half of any polygon.
Retail expansion teams in LA must model AM-peak, midday, and PM-peak isochrones as separate trade areas — a daypart-sensitive concept (breakfast QSR vs. dinner fast-casual) will see materially different addressable populations depending on which is used. Sub-markets like the Westside, South Bay, San Fernando Valley, San Gabriel Valley, and OC behave almost as independent metros for drive-time purposes, and brands should template trade areas per submarket rather than relying on a single LA-wide rule.