NC: Various Point Concerns Around Charlotte and along NC 16 and US 21

[Markkos1992]

US 421:  NC16>-NC16_N

US 421 BUS (Wilkesboro):  At minimum, I recommend the following:

1.  Add a point at Speedway Rd for access to North Wilkesboro Speedway.  (also affects NC 115)
2.  Make the shaping point north of NC18/268_S visible and label it DSt_E or 6thSt_N.
3.  Add a point at CBD Loop for where NC 18 SB/NC 268 WB leaves US 421 BUS NB.

NC 10: The NC16Bus points should be S and N instead of W and E.

NC 16:
1. Consider replacing shaping points with visible points.
2.  A point should be added at Rock Barn Rd.  (direct connection to I-40)
3.  WayChuRd should be slightly relocated.
4. AspDamRd>-AlsDamRd
5. Consider replacing WalLn with a nearby point. 
6. US421_E>-US421(286A)
7. NC268>-US421(286B)
8. US421BusWil>-US421Bus (optional IMO)
9. US421_W>-US421_N

NC 16 BUS (Conover):  7thSt>-7thStPl (I think)

NC 18:  I recommend moving the CBDLoop to the CBDLoop/Wilkesboro Blvd intersection where the directions split.  (also affects NC 268 obviously)

NC 115: I would change US421Bus_N to NC18/268.  Technically fine as-is though.

NC 163: Consider replacing shaping points with visible points.