We only have one car tunnel that I am aware of and it is near Goleta, down near Santa Barbara, on the coast highway. Not very long and through mostly solid rock if I remember correctly.
Kristen, if you don't like tunnels then you would definitely not like riding BART under the San Francisco Bay. And especially when you are at the halfway point and the power fails. Lots of people get panicky until emergency lights come on and they do have a way to exit on foot via the maintenance tunnel in between the two main train tunnels..
Ron
