On that section of I-5 there is minimal traffic at that time because I make the commute past there every morning and was surprised to see so many cars backed up from near downtown Seattle. I drove past the scene at around 8 and saw his Jeep and thought to myself I hope that person is okay because the roof was completely caved into the front cabin and there were pieces of his vehicle for a good 100 feet.

Don't assume he was speeding in traffic because like I said, traffic is virtually non-existent at that time for that section (exit 154b) except for the left side going to I-405. Can't really know who was at fault but I'm guessing someone tried to take last minute exit to the airport and started it. Condolences to his family.