When I first moved to LA I spent a lot of time before meetings sitting in my car on suburban streets in the middle of the day, waiting, like a pedophile. I had no idea how long it would take me to get anywhere so I erred on the side of caution or a potential three lane, 10-car fire on the 101, and left early for everything. I realized the time of arrival suggested on the GPS would only be accurate if everyone else in LA were eaten by zombies and it was only me and my trusty German Shepard in a fabulous townhouse. Speaking of GPS, never speak of a GPS to anyone who moved to LA at least ten years ago. They will all insist GPS is shit and it's Thomas Guide or nothing. Yes, my GPS has put me on some weird, inconvenient routes but I always got there and never rear-ended a car because my head was sunk into a giant book of maps instead of looking ahead. The aversion to GPS by LA vets is a middle-aged version of "when I was your age I walked uphill to school in snow with no shoes..."
Now that I have a grasp of how long it'll take me to get to most places, I still find myself to be the first one there. I've sat at stand-up shows 15 minutes before they're supposed to start and it's just me and the busboy. I've walked into bars and restaurants five minutes past the time I'm supposed to meet someone, and still have to text the other person fifteen minutes later to see where they are. Traffic or not, lost or not, there's really no urgency to communicate an excuse or an ETA to the other person who is waiting for you. I think there's some general, unspoken rule that perfectly responsible, considerate people know and I haven't figured out yet: meeting times are only mark rough half hour windows of time and there's no need to apologize or acknowledge your tardiness as long as there's a chance of potential, unexpected traffic or parking restrictions.