For anyone interested, here is a link where the recording of the Big Dig talk from my latest blog can be downloaded.  It will download as an executable file to watch.  Of particular interest to our discussion of the interaction of the public and engineering is the first section on history (5:00 to 23:00) and the personal observations (1:05:00 to 1:07:00).

https://docs.google.com/open?id=0B8lbtIhiQZ_vVkVGUy1ORGN3alE