The marathon slows things down considerably, as you may expect. Every year, LIFE has an event that falls on Marathon Sunday. And every year, I travel from Kaimuki to KokoHead during peak marathon time.
They contraflow Kalanianaole between Kahala and Aina Haina, then route traffic up into Aina Haina, over to Hawaii Kai, then abandon it. No sighs after you get into Hawaii Kai, so I always end up lost at least once trying to find my way out.
It takes over an hour.