Hey Bob! - We've done many trips to Carmel/Monterey/San Francisco taking the famous Hwy 1 along that spectaular coast. Apparently, this Devil's Slide tunnel will bypass a portion of Hwy 1 about 15 miles south of San Francisco. This section of Hwy 1 always gave us chills thinking about how many times that portion of roadway had huge boulders crash down onto the road or how many times a section of that roadway collapsed and tumbled several hundred feet down to the ocean.
I will definitely make it a point to film our first passage through that mile-long tunnel. Posted speed limit through the single lane tunnel is 45MPH! I wonder if it says anything about not honking loud air-horns?