Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Confusion; Situational Awareness; Troubleshooting
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Ground Equipment Issue
General None Reported / Taken
ATC Equipment / Nav Facility / Buildings; Environment - Non Weather Related; Airport
I have noticed that there are a number of taxiway signs at SeaTac airport that have taxiway identifiers on only one side of the sign.  For example when taxiing northbound on [Runway] 34C the right turn for Taxiway M is not shown.  However; when taxiing southbound on 16C Taxiway M is depicted on the taxiway sign.  There are numerous signs that exist; with information on only one side; or possibly a sign needs to be installed for some of these turnouts. This is becoming more noticeable as ATC is frequently parking aircraft on taxiways holding short of 16L/34R when their gates are occupied. This can be especially problematic to see a taxiway that is a reverse high speed in the dark and in the rain. Have the Port of Seattle install taxiway signage that is appropriate for each taxiway regardless of the direction of travel so taxiways are easily identified regardless of direction of travel.
Air Carrier Captain reported taxiway identifiers need improving at this location.