Currently State Route 99 runs through downtown Seattle via the Battery Street Tunnel and the Alaskan Way Viaduct. Real life plans call for the Viaduct portion to be moved to a tunnel (Big Dig style).

The street maps in SR1 and Seattle Sourcebook do not show either the tunnel or the viaduct, but larger scale maps still show Route 99. No writeup of the Renraku Arcology (that I could find) even mentions Route 99.

So what happened to the downtown portion of this highway? Did the Arcology break it into two unconnected segments (north and south) ? or does it go around the Arcology on the waterfront ?

Speculation is welcome, but a canon answer with a source would be awesome.

The Ghost Dance made it disappear.

Maybe it became the SR Universe's version of Danny The Street?

What about Johnny LaRue?

So, reading the Wiki page - that's actually a pretty cool idea. I know that the Sixth World is supposed to be sorta "grimdark" (not how I run it, but how CGL and most of the fandom seem to prefer it) but that just sort of fits in its own way. It's not always all about shedim and dragons and immortal elves - sometimes things just get plain weird. And it's not entirely out of scope, I mean, we do have city spirits.

I would simply assume, it goes right through the arc (either above or below groundlevel), if that area was where it used to be, just like the monorail and the bus tunnles...

SR is as grimdark as you want it to be. It has unicorns and faeries and sparkly vampires and good looking were wolves and casper the spirits . . With a twist of course.
As for Danny the street . . what the hell were they smoking? O.o
And worse . . A Free City Spirit Great Form COULD pull this off . .

Let's see what I can recall...

In one of the early books - it may have been Dreamchipper, but forgive me if I'm wrong - the 99 was still an elevated freeway. Then, I think in Brainscan or in the 2nd edition Seattle writeup in the core book, it was implied to be a tunnel that ran adjacent to the underground bus tunnel - the same one that ran under the Arcology, which got blocked up and guarded during the lockdown. I've always assumed it ran under the Arcology, personally.

I looked at those sources and didn't find anything. I also went over Arcology Shutdown again, and there is no mention of Route 99 therein (including the getting in and out sections). I have to conclude that Route 99 doe not go through or under the Arcology. (despite my apparently false recollection to the contrary).

I suspect I'll have to go through all the old adventures to see if I can find any mention of the Route north of the Arcology.