N.C. 155 signs started showing up on the old U.S. route around 1995, mostly in the Boger City area. Signing was erratic, however -- some parts of the old route were still signed as mainline 321, even a few years after the freeway was built. Exit signs off the new freeway sometimes called the old road 321, or gave it no number at all. And nobody liked the number -- especially people in Newton and Conover, who decried the loss of their U.S. highway. (The new 321 veers completely away from those towns; old 321 went through them.) As it turned out, few if any 155 signs showed up in Newton or Conover; the 321 signs were never taken down there. 

When the 321 freeway was finished all the way to Hickory in December 1998, the state announced it would rename 155 (such as it was) as Business 321. 155 was dead by February 1999, when the sign change was completed. This fact is belied by the 1999 official state map (right), however, which was published in September 1998 before the change.

In 1987 or 1988, 157 was extended south over a previously unnumbered road to its current terminus in Durham.

159 reached all the way to Business 220 by 1977.