bottom level of the double decker bay bridge (80) in san francisco has great acoustics especially in the tunnel as it passes treasure island... 2nd gear redline for 4 MILES of intense invidia music

 

For those of you who are in the LA area... there are some tunnels in the Santa Monica Mountains that are spectacular. There is only one lane in each direction; it starts out with a corrugated steel pipe on either end, then the central section is straight rock. A couple of these tunnels are 1-way only... my oh my!