I've seen this in many tunnels, particularly in Asia. I've always been quite curious about them. But where do emergency exits in tunnels, like this one (https://www.google.com/maps/@37.7198626,127.0142032,3a,75y,299.01h,91.21t/data=!3m6!1e1!3m4!1s-VQZGR4iPt46SJBhK1ZBEA!2e0!7i13312!8i6656), lead to? There's also a variation with a chamber reminiscent of a garage, with a car logo.
As a child, I always thought they took you to some underground stairway that took you all the way up to the surface, but now I know that that's unlikely. Didn't wanna find out firsthand, obviously.
More than likely, the doorway just leads you to the next tube with traffic going in the opposite direction.
I'm most familiar with the Anton Anderson tunnel in Alaska, a 2.5 mile long one-lane tunnel converted from rail-only to shared (carefully!) by trains and both directions of car/truck traffic.
In addition to pullouts for disabled vehicles, emergency "safe houses" were excavated about every one-third mile (http://dot.alaska.gov/creg/whittiertunnel/tundesign.shtml), for travelers to await rescue. The mountain the tunnel was bored through is too high and wide (http://www.alaskaroads.com/whittier-tunnel-west-portal-overview-large.jpg) for DIY escape routes to be practical.
I vaguely recall that the rail tunnels between England and France have emergency exits leading to a ventilation tunnel between the twin tubes.
Quote from: jeffandnicole on November 11, 2020, 11:25:04 AM
More than likely, the doorway just leads you to the next tube with traffic going in the opposite direction.
What about this? (https://www.google.com/maps/@35.0965325,132.8888308,3a,75y,156.4h,103.3t/data=!3m6!1e1!3m4!1svJGWQMqtzHiIZyoYX-L5yA!2e0!7i13312!8i6656)
I think I saw a stairwell here: https://www.google.com/maps/@49.1218502,-123.0755513,3a,75y,56.64h,82.68t/data=!3m6!1e1!3m4!1sLJQw_DRd6PQX6insoH8FZQ!2e0!7i13312!8i6656
In Seattle, the Battery Street "Tunnel" (cut and cover, one level down) has this staircase (https://goo.gl/maps/S9P15NET6SKLWviX7) to the surface. The tunnel has since been closed and filled in since the opening of a new deep bore tunnel that replaced the Alaskan Way Viaduct.
Quote from: ErmineNotyours on November 11, 2020, 10:31:14 PM
In Seattle, the Battery Street "Tunnel" (cut and cover, one level down) has this staircase (https://goo.gl/maps/S9P15NET6SKLWviX7) to the surface. The tunnel has since been closed and filled in since the opening of a new deep bore tunnel that replaced the Alaskan Way Viaduct.
If you look inside the segment of the new tunnel that passes through the same area, there is actually an emergency exit there! I wonder if they somehow managed to repurpose the old emergency exit.
Quote from: TheGrassGuy on November 12, 2020, 08:36:52 AM
Quote from: ErmineNotyours on November 11, 2020, 10:31:14 PM
In Seattle, the Battery Street "Tunnel" (cut and cover, one level down) has this staircase (https://goo.gl/maps/S9P15NET6SKLWviX7) to the surface. The tunnel has since been closed and filled in since the opening of a new deep bore tunnel that replaced the Alaskan Way Viaduct.
If you look inside the segment of the new tunnel that passes through the same area, there is actually an emergency exit there! I wonder if they somehow managed to repurpose the old emergency exit.
The new tunnel is much, much deeper than the old tunnel, so there is no repurposing. The emergency exits within the new tunnel lead out to a parallel corridor within the bore:
(https://www.wsdot.wa.gov/Projects/Viaduct/Media/Default/-NewDocuments/ProgramSpotlight/2017/Breakthrough/ventilationgraphic2015_web.jpg)
The actual exits are near the portals and look like small subway entrances: https://goo.gl/maps/Sy5q3SJ3sW5Jko1dA
Quote from: jeffandnicole on November 11, 2020, 11:25:04 AM
More than likely, the doorway just leads you to the next tube with traffic going in the opposite direction.
That's the way I-49/Bobby Hopper Tunnel is set-up. Go through the door to avoid a fire (or other problem) , come out in the middle of traffic and get run over :o :o ;)