>  MR> explosion or fire wasnt enough to collaspe a wall, the smoke would
 >  MR> fill the tunnel iun less then 5 min, with the tunnel being over 3
 >  MR> miles
 >  MR> long, and trafic always coming in it would be a mess, there have been
 >  MR> small fires in there before that have caused massive accidents. So a
 >  MR> larger fire could cause even more caose
 > They could also explain just what kind of ventilation
 > equipment is in
 > use.  Heck, they might even offer you a tour for your
 > class.  In fact,
 > you would most likely be amazed just how a tunnel is
 > actually put
 > together, and all the behind the scenes things that
 > goes on there!
This brings to mind something I saw up in that area (don't know what state, 
but I'd guess it was in New Jersey, Delaware, or Maryland) about 30 years 
ago:  On the approach to a tunnel, there were signs saying that vehicles 
with, or pulling trailers with, gas bottles were not to use the tunnel, but 
were instead to use an open-air route.  The driver of the car I was in failed 
to acknowledge these signs, and we were pulled over and requested to take 
that other route.  Might some tunnels have less than optimum attributes?
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