What is the gray zigzag line over V154 between Dublin VORTAC and LOTTS intersection?
According to the “Airspace Information” section of FAA Aeronautical Chart User’s Guide, it is a low-altitude unusable route. The high-altitude flavor is similar in shape with a smaller amplitude.

See also page 62 of the Guide PDF, if you prefer.


  UNUSABLE ROUTE 


In this particular case, observe the overprint on 110 in the compass rose surrounding DBN, which indicates abnormal status. The Airport/Facility Directory entry for Dublin VORTAC (as of the 31 MAR 2016 publication) reads, with added emphasis:


  DUBLIN N32°33.81′ W82°49.80′ NOTAM FILE MCN.
  &nbsp;&nbsp;(L) VORTAC
   113.1   DBN   Chan 78   276º 7.9 NM to W H 'Bud' Barron. 306/5W.
  HIWAS.
  &nbsp;&nbsp;&nbsp;&nbsp;VOR portion unusable:
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;215°–285° byd 10 NM blo 3,500’
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;001°–139° byd 33 NM
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;001°–139° blo 5,000’
  RCO
   122.1R 122.6 113.1T (MACON RADIO)


Note that the DBN 110 radial falls within the 001-139° unusable range. Beyond LOTTS intersection, V154 is defined with reference to the Savannah VORTAC.