Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Distraction
Deviation / Discrepancy - Procedural Clearance; Ground Incursion Taxiway
Flight Crew Became Reoriented
Manuals; Human Factors
On taxi out from Spot 80; Ground gave taxi instructions 'taxi to Runway 30 via Z; Y11.' However at that same time [a company] aircraft was exiting the runway head on with us at taxi way delta. I was not sure what directions they were given by Tower because they were on a different frequency. They had the taxi light on and directed at us so I gave pause looking to give way to the head on traffic. At the same time a third RJ was south bound on Y with his taxi light on. I gave pause to watch the situation and keep from getting stuck head to head with no way out.  When the other aircraft signaled by turning off its taxi light we proceeded with a south turn on 'Y' and I knew I had passed 'Z.' Factors and recommendations.1. An XA:15 report east coast time; with a non Part 117 legal rest period. 2. Change [in departure concourse] caused my eyes to want to look at spot 82 vs. 80 due to the fact we parked at a different location.3. The RJ that exited the runway facing us at D had taxi lights on; [which was a] 'distraction;' I was expecting him to move toward us and the RJ on Y turned off his taxi lights to signal he was giving way. 4. The Airport Diagram has an E in the middle of Taxiway Z. [This] 'needs to be changed.'   5. On the Airport Diagram a dash line box [Comm. boundary] runs down the center of Taxiway 'Y.' It needs to be moved like it is on the east side of the airport so as not to run down a taxiway. 6. On the Airport Diagram add a Z south of D to indicate the taxiway.
Air Carrier Captain reports a taxiway incursion at IAD due to distractions and deficiencies in the Airport Diagram.