Why are there two Interstates 76, 84, 86 and 88?
All duplicates but 86 arose around the time when most letter suffixes on Interstates were removed, though not all replaced a suffixed Interstate designation. Eastern I-86 (see 6.3.6) was recently added because there were no other choices that would fit. At one time, an eastern I-86 existed from Hartford, CT to I-90 in MA; this is now part of I-84 (see http://www.kurumi.com/roads/ct/i86.html ). There were also two I-39s, but I-39 is now signed along I-90 between the two sections (see http://www.interstate-guide.com/i-039.html ). There are technically two I-74s, but these are planned to be connected, unlike the other duplicates (see Question 6.3.4 ). I-90, interpreted by some two be in two segments, is actually continuous (see Question 6.3.10 ). At one time two I-77s and two I-82s were planned (see http://www.roadfan.com/5758int.html ). Apr 5, 2007 6.2.5 Q: Which 3di spurs go both directions from a parent? A: I-305 CA (hidden), I-516 GA, I-526 SC, I-540 AR (small overlap with I-40), I-17
