Three different sets of distributions of forecast air travelers among the commercial airports were made-one for each of the three assumptions described in Chapter II. They are repeated below for reference: Case I: Case II: Case III: All three airports were assumed to be operating and to be expandable in an unrestricted manner. Washington National Airport was assumed to be closed, while the other two airports were assumed to be operating and to be expandable in an unrestricted manner. All three airports were assumed to be operating; however, operations and traffic volumes were assumed to be restricted at Washington National Airport, while the other two airports were assumed to be unrestricted in their operations and to be expandable in an unrestricted manner. As discussed in Chapter II, competition from either V/STOL or high speed rail service, or both, may significantly alter conventional air travel demands beginning in 1980. Four possible situations have been analyzed in this regard. Situation A: Only V/STOL service will be developed and in competition with conventional air travel by 1980. Situation B: On high speed rail service will be developed and in competition with conventional air travel by 1980. Situation C: Both V/STOL and high speed rail will be developed and in competition with conventional air travel by 1980. Situation D: No competition with conventional air travel will be offered by Table 1 shows the forecast annual number of enplaned passengers at each airport, by five year intervals, under any combination of the assumptions regarding the operation of Washington National Airport and competition from V/STOL and high speed rail service. It can be seen from the table that if operations at Washington National are restricted and no competing service is available (Case III, Situation D), the number of enplaned passengers per year at Dulles would exceed 24 million by 1990. By contrast, the same airport would only expect 17 million enplaned passengers in 1990, if operations at Washington National are restricted and competition is available from both V/STOL and high speed rail service (Case III, Situation C). Table 2 compares the present runway capacities of the Region's three commercial airports with the forecast number of operations for each of the three cases in which no competition is assumed. The following conclusions can be drawn from this table: Case III-D would best use existing capacity and minimize the needs for expanding runway capacity. However, even in Case III-D, some expansion would be needed at both Dulles and Friendship airports before 1990. Case II-D would require expansion at both Dulles and Friendship before 1975. Case I-D would not require expansion at either Dulles or Friendship within the forecast period, but Washington National Airport would have to more than double its runway capacity-a requirement which seems highly unlikely to be satisfied. |