Former Seattle (now Las Vegas) resident here. To make the buses run on time, the planners build in "time stops." These are locations where the bus should go through at specific times to not be too early for the rest of the schedule, and they also provide some buffer for buses to recover time lost due to bike loading, disabled passengers, and traffic congestion. If you're getting the bus after a time stop, you'll likely almost always get it on time. If your stop is before the time stop, bus arrival times will vary wildly.
It gets even more interesting when you add transport of the bus: the Seattle (King County) Metro also serves Vashon Island, so some of the buses travel on ferries with their associated delays and peculiarities.
I get on a bus right before a time stop. It's only about 30 blocks after the previous time stop (Northgate TC) but has arrived as soon as 5 minutes before the posted time. That's always fun when combined with a 10 minute late bus following it.
It always stings to see the bus approach early such that I have to run for it, only to then have it wait for 5 minutes at the time stop 2 stops later.
> some of the buses travel on ferries
That's an interesting that they would do that along an entire route rather than splitting the two. I've never heard of that before.
I also do really like how Seattle has that dedicated busway twice a day. It's one of the avenues downtown right?
It gets even more interesting when you add transport of the bus: the Seattle (King County) Metro also serves Vashon Island, so some of the buses travel on ferries with their associated delays and peculiarities.