The page you are looking for has been split into two new pages and relocated.

http://www.hawaiihighways.com/FAQs-page3.htm

The new page 3 includes, among others, this item on a supposed former "U.S. route" system in Hawaii:

http://www.hawaiihighways.com/FAQs-page3.htm#old-route-shields

Section 4 of the FAQs (Interstates) is now at:

http://www.hawaiihighways.com/FAQs-page4.htm

The new page 4 includes, among others, items on why Hawaii has interstates:

http://www.hawaiihighways.com/FAQs-page4.htm#why-Interstates

and the mysterious Interstate H-201:

http://www.hawaiihighways.com/FAQs-page4.htm#H-201

Please update your bookmarks, favorites, etc. accordingly.