Central area

Final configuration:

The SR 99 tunnel will be approximately two miles long. It will feature two 11-foot travel lanes in each direction, bordered by an eight-foot safety shoulder and a two-foot shoulder. Long, gentle curves will allow for safe sight distances. The southbound lanes are stacked above the northbound lanes, so drivers will not see oncoming traffic.

Tunnel cross-section

The tunnel will be built to modern earthquake standardsThere will be no on- or off-ramps between the two tunnel portals. In the event of an emergency, exits every 650 feet provide shelter and escape routes, while a state-of-the-art safety and ventilation system assists first responders, and fights fire and fumes. (Read more about the tunnel's safety systems in the program library.)