from 2001--White Paper from Dept of Transport (USDOT) on vulnerabilty of US transportation network--

It remains very vulnerable, and anyone who has driven through a US tunnel, say Lincoln Tunnel, will attest to that.

d t won't mind as goes by helicopter.

sigh sigh

https://www.planning.dot.gov/documents/SecurityPapers/SecurityConsiderations_Polzin.htm

1-14-2017