Page 183 - Planning and Design of Airports

150 Airp o r t Pl anning

airport master plan or an airport system plan. These estimates deter-
mine the future needs for which the physical facilities are designed. A
financial plan to achieve the recommended staged development
along with required land-use zoning usually accompanies the plan. It
should be apparent that an airport is designed for a projected level
and pattern of demand and changes in the magnitude or characteris-
tics of this demand may require facility modifications or operational
measures to meet changing needs. Facility planning is necessary to
provide adequate levels of service to airport users.
The development of accurate forecasts requires a considerable
expense of time and other resources because of the complex methodolo-
gies which must be used and the extensive data acquisition that is often
required. The usual justification for a demand forecast in an aviation
plan is that the expected level of uncertainty associated with the estima-
tion of essential variables will be reduced, thereby reducing the probabil-
ity of errors in the planning process and enhancing the decision-making
process. The implication, of course, is that the benefits gained due to a
better knowledge of the magnitude and fluctuation in demand variables
will outweigh the costs incurred in performing the forecast.
To assess the characteristics of future demand, the development
of reliable predictions of airport activity is necessary. There are numer-
ous factors that will affect the demand and planners who are prepar-
ing forecasts of demand or updating existing forecasts should consider
local and regional socioeconomic data and characteristics, demo-
graphics, geographic attributes, and external factors such as fuel costs
and quality of service parameters. Political developments, including
rising international tensions, changes in security, airline delays and
congestion, and travel attitudes, will impact demand. Actions taken
by local airport authorities, such as changes in user charges, can also
stimulate or hinder the demand and investment decisions made as
the result of the planning process itself can also produce change by
removing physical constraints to growth [2].
Over the years, certain techniques have evolved which enable air-
port planners and designers to forecast future demand. The principal
items for which estimates are usually needed include
• The volume and peaking characteristics of passengers, air-
craft, vehicles, and cargo
• The number and types of aircraft needed to serve the above
traffic
• The number of based general aviation aircraft and the num-
ber of movements generated
• The performance and operating characteristics of ground
access systems
Using forecasting techniques, estimates of these parameters and a
determination of the peak period volumes of passengers and aircraft