PHOTOS: Sneak peek at Seattle's new mega tunnel

Seattle's SR 99 tunnel will have cellular phone service, sprinklers in case of fire and a pedestrian escape route.

It has 107 portable potties right now, but don't get your hopes up about mid-commute bathroom breaks. The potties will all be removed when construction is complete — possibly as early as fall of this year.

The state transportation department and Seattle Tunnel Partners allowed journalists to ride inside the tunnel on Tuesday, showing squared-off walls and driving surfaces that are expected to be complete within days. The shape of Bertha is only visible in the vaulted ceiling of the southbound lanes, which are on the tunnel's upper deck, and in the pedestrian escape route. Bolts holding one cement ring against another are clearly visible.

The Alaskan Way Viaduct is being replaced by a tunnel because of the danger it poses in an earthquake. (The 2001 Nisqually quake damaged the structure.) A tunnel is safer because it is circular and underground.

But building a tunnel below downtown Seattle turned out to be a daunting task. The boring machine — nicknamed Bertha — broke down early in the project. Bertha ended up requiring a two-and-a-half year rescue mission, in which the machine was raised it to the surface, fixed and eventually put back to work.

Now we can finally discuss previously undreamed-of things, like tunnel livability. A few facts about what life will be like inside Seattle's new tunnel:

• There will be no WiFi. (Because you're not supposed to be streaming anything while driving, of course.)
• There will be cellular service, because people need to be able to call 9-1-1.
• Tunnel walls are being painted white. And yes, WSDOT plans to wash them.