Figure 14-18.  Taxiway Bravo direction sign with a collocated  Taxiway Delta location sign. When the arrow on the direction  sign indicates a turn, the sign is located prior to the intersection.  Figure 14-20A  and  B  shows an example of a direction sign at  a complex taxiway intersection.  Figure 14-20A  and  B  shows  Taxiway Bravo intersects with Taxiway Sierra at 90°, but at  45° with Taxiway Foxtrot. This type of array can be displayed  with or without the taxiway location sign, which in this case  would be Taxiway Bravo.  At most towered airports, the enhanced taxiway centerline  marking is used to warn you of an upcoming runway. It consists  of yellow dashed lines on either side of the normal solid taxiway  centerline and the dashes extend up to 150 feet prior to a  runway holding position marking.  [Figure 14-21A  and  B]  They  are used to aid you in maintaining awareness during surface  m ov ement to reduce runway incursions.  Destination signs have black characters on a yellow  background indicating a destination at the airport. These  Enhanced Taxiway Centerline Markings  Destination Signs  Figure 14-19.  Surface painted taxiway direction signs.  14-12  signs always have an arrow showing the direction of the taxi  route to that destination.  [Figure 14-22]  When the arrow on  the destination sign indicates a turn, the sign is located prior  to the intersection. Destinations commonly shown on these  types of signs include runways, aprons, terminals, military  areas, civil aviation areas, cargo areas, international areas,  and fixed-base operators. When the inscription for two or  more destinations having a common taxi route are placed  on a sign, the destinations are separated by a “dot” (•) and  one arrow would be used as shown in  Figure 14-22.  When  the inscription on a sign contains two or more destinations  having different taxi routes, each destination is accompanied  by an arrow and separated from the other destination(s) on  the sign with a vertical black message divider as shown in  Figure 14-23.  The example shown in  Figure 14-23  shows  two signs. The sign in the foreground explains that Runway  20 threshold is to the left, and Runways 32, 2, and 14 are to  the right. The sign in the background indicates that you are  located on Taxiway Bravo and Taxiway November will take  you to those runways.  The instrument landing system (ILS) broadcasts signals to  arriving instrument aircraft to guide them to the runway. Each  of these ILSs have critical areas that must be kept clear of all  obstacles in order to ensure quality of the broadcast signal. At  many airports, taxiways extend into the ILS critical area. Most  of the time, this is of no concern; however, during times of  poor weather, an aircraft on approach may depend on a good  signal quality. When necessary, ATC will protect the ILS  critical area for arrival instrument traffic by instructing taxiing  aircraft to “ hold short ” of Runway (XX) ILS critical area.  The ILS critical area hold sign has white characters, outlined  in black, on a red background and is installed adjacent to the  ILS holding position markings.  [Figure 14-24]  The holding  position markings for the ILS critical area appear on the  pavement as a horizontal yellow ladder extending across the  width of the taxiway.  When instructed to “hold short of Runway (XX) ILS critical  area,” you must ensure no portion of the aircraft extends  beyond these markings.  [Figure 14-25]  If ATC does not  instruct you to hold at this point, then you may bypass the ILS  critical area hold position markings and continue with your  taxi.  Figure 14-24  shows that the ILS hold sign is located  on Taxiway Golf and the ILS ladder hold position marking  is adjacent to the hold sign.  Holding Position Signs and Markings for an  Instrument Landing System (ILS) Critical Area 