Page 267 - Planning and Design of Airports

228 Airp o r t D e sign

D E
DISPLACED THRESHOLD
2B
2C
A
FIXED OBJECT
RUNWAY END

DISPLACED THRESHOLD
SLOPE

A FIXED OBJECT
RUNWAY END

DISPLACEMENT NECESSARY
FIGURE 6-32 Use of displaced threshold, runway siting requirements.

Taxiways and Taxilanes
Taxiways are defined paths on the airfield surface which are estab-
lished for the taxiing of aircraft and are intended to provide a linkage
between one part of the airfield and another. The term “dual parallel
taxiways” refers to two taxiways parallel to each other on which air-
planes can taxi in opposite directions. An apron taxiway is a taxiway
located usually on the periphery of an apron intended to provide a
through taxi route across the apron. A taxilane is a portion of the air-
craft parking area used for access between the taxiways and the aircraft
parking positions. ICAO defines an aircraft stand taxilane as a portion
of the apron intended to provide access to the aircraft stands only.
In order to provide a margin of safety in the airport operating
areas, the trafficways must be separated sufficiently from each other
and from adjacent obstructions. Minimum separations between the
centerlines of taxiways, between the centerlines of taxiways and taxi-
lanes, and between taxiways and taxilanes and objects are specified
in order that aircraft may safely maneuver on the airfield.

Widths and Slopes
Since the speeds of aircraft on taxiways are considerably less than on
runways, criteria governing longitudinal slopes, vertical curves, and
sight distance are not as stringent as for runways. Also the lower
speeds permit the width of the taxiway to be less than that of the
runway. The principal geometric design features of interest are listed
in Tables 6-18 and 6-19 for the FAA. ICAO standards are listed in
Tables 6-20 and 6-21.