construction workers as well.
LOL
Why am I looking at a studio?
For those of you who can understand such engineering terms, I found a link from the Corp of Engineers with specs for the Mississippi River system. On page 104 (in my Adobe browser) it shows the I35 Bridge information in St. Paul. Maybe one of your engineering type of people can explain all of this in layman’s terms.
http://www.navcen.uscg.gov/pubs/LightLists/V5COMPLETE.pdf