Airport Taxi Line Thickness: What's The Standard Wait Time?

Taxiways are the roadways that airplanes use to get to and from runways. They are differentiated from runways by the colour of their markings—all runway markings are white, while taxiway markings are yellow. The taxiway centre line is typically between 6 and 12 inches wide. Taxiways also have edge markings, noted by double solid yellow stripes on each edge.

Taxiway markings are standardised worldwide

Taxiways are identified by a letter, which is spoken in the phonetic alphabet. For example, Taxiway A is "Taxiway Alpha" and so on. Some airports with more complex layouts name their smaller taxiways based on the larger ones. For instance, short connecting taxiways off the main Taxiway A might be called Taxiway A1 or Taxiway AB.

Taxiways also have edge markings, indicated by double solid yellow stripes on each edge. These double stripes may be solid or dashed. A dashed line can be crossed, but a solid line indicates that it should not be.

Taxiway shoulder markings show pavement edges or aprons. These are marked with yellow hashes painted at angles to the taxiway.

When a taxiway crosses another taxiway or ramp, and a pilot is expected to hold, a single dashed yellow line marks it. This is painted perpendicular to the taxiway.

Hold short bars are another marking used to indicate that a pilot needs to stop. These are four yellow lines painted perpendicular to the taxiway, two solid and two dashed. The dashed side always faces the runway.

Enhanced taxiway centreline markings are used as an inexpensive way to draw attention to hazardous intersections. These are dashed lines, painted on each side of the taxiway centreline as the taxiway approaches the hold short line.

Taxiways are differentiated from runways by the colour of their markings

The taxiway centerline is a single continuous yellow line, 6 to 12 inches (15 to 30 cm) in width. This marking helps aircraft stay centred while taxiing. There is also an enhanced taxiway centreline, which consists of a parallel line of yellow dashes on either side of the normal taxiway centreline. This enhanced marking is used to warn pilots that they are approaching a runway.

Runway markings are white. The runway centerline is a dashed white line that runs down the middle of the runway, guiding pilots during takeoff and landing. The runway threshold markings, a series of white stripes at the runway's beginning, indicate where the landing runway starts.

The yellow markings on a taxiway indicate areas not intended for aircraft use, such as soft ground or obstructions. Taxiway edge markings define the edge of the taxiway when it does not correspond with the edge of the pavement. Taxiway shoulder markings indicate the paved area of a taxiway that is not intended for aircraft use.

In addition to the colour of the markings, the width of the lines also differs between taxiways and runways. Taxiway centreline markings are typically 6 to 12 inches (15 to 30 cm) wide, while runway centreline markings consist of stripes that are 120 feet (36.5 m) in length and gaps that are 80 feet (24.3 m) in length.

Taxiway edge markings define the taxiway's lateral limits

Taxiway edge markings are used to define the taxiway's lateral limits when the taxiway's edge does not correspond with the edge of the pavement. There are two types of taxiway edge markings: continuous markings and dashed markings.

Continuous Markings

Continuous taxiway edge markings consist of a continuous double yellow line, with each line being at least 6 inches (15 cm) in width and spaced 6 inches (15 cm) apart. These markings are used to define the boundary between the taxiway and the shoulder or another paved surface not intended for aircraft use.

Dashed Markings

Dashed taxiway edge markings consist of a broken double yellow line, with each line being at least 6 inches (15 cm) in width and spaced 6 inches (15 cm) apart. These markings define the edge of the taxiway on a paved surface where the adjoining pavement is intended for aircraft use, such as an apron. Dashed markings allow aircraft to cross the lines as needed, for example, to turn onto a parking apron.

Taxiway Shoulder Markings

Taxiways, holding bays, and aprons may be provided with paved shoulders to prevent blast and water erosion. Taxiway shoulder markings are yellow lines perpendicular to the taxiway edge, extending from the taxiway edge to the pavement edge, and are typically about 3 metres long. These shoulders are not designed to support aircraft and may be unable to bear their load.

Taxiways are identified by a letter, spoken in the phonetic alphabet

Taxiways are the roadways that airplanes use to get to and from the runway. They connect the runway with the ramp and parking area. Each runway usually has one or more parallel taxiways, with several smaller taxiways allowing landing aircraft to get off the runway quickly.

Taxiways are identified by a letter, and each letter is spoken in the phonetic alphabet. So, Taxiway A is expressed as "Taxiway Alpha" on the radio. Taxiway B is "Bravo", C is "Charlie", and so on. This is done to avoid confusion, as it is easier to differentiate spoken letters that sound different ("Alpha, Bravo, Charlie") than those that sound similar ("D, E, F").

Some complex airports name their smaller taxiways based on larger ones. Short connecting taxiways off of the main Taxiway A might be called Taxiway A1 or Taxiway AB.

At large airports where there are more taxiways than letters of the alphabet, double-letter designators may be used for minor taxiways or taxiway stubs. For example, a small taxiway branching off of the main Taxiway A might be called Taxiway AA or Taxiway AB.

The letters 'O', 'I', and 'X' are not used for taxiway designations. This is because 'O' and 'I' can sound similar to numbers over the radio, and 'X' is used internationally to indicate a closed taxiway or runway.

Taxiways are the routes aircraft travel from and to passenger terminals and runways

Taxiways are the routes aircraft use to travel to and from passenger terminals and runways. They are the roadways that connect the runway with the ramp and parking area. Each runway usually has one or more parallel taxiways, with several smaller taxiways allowing landing aircraft to get off the runway quickly. Taxiways are differentiated from runways by the colour of their markings—all runway markings are white, while taxiway markings are yellow.

Taxiways are identified by a letter, and each letter is spoken in the phonetic alphabet. For example, Taxiway A is expressed as "Taxiway Alpha" on the radio. Some complex airports name their smaller taxiways based on larger ones. Short connecting taxiways off the main Taxiway A might be called Taxiway A1 or Taxiway AB.

The most crucial marking of a taxiway is the centreline stripe. It is a single solid yellow stripe. Some taxiways also have edge markings, noted by double solid yellow stripes on each edge. These double edge stripes may be solid or dashed. A dashed line can be crossed, but a solid line indicates that it should not be.

The wings of a plane extend a long way to the left and right of the pilot, so it is easier for them to drive by focusing on keeping the middle of the plane over the centreline stripe. Since taxiways are built for aeroplanes, there should be no obstacles on either side to worry about. However, pilots do keep an eye out for things sticking up, as the wings of many planes extend beyond the paved edges of the taxiways.

Taxiway shoulder markings show pavement edges or aprons. If these are located where aircraft are not intended to be operated, they are marked with yellow hashes painted at angles to the taxiway.

Finally, if a taxiway crosses another taxiway or ramp, and a pilot is expected to hold there, a single dashed yellow line will mark it. It will be painted perpendicular to the taxiway.

Taxiway Markings and Signs

All taxiways should have centreline markings and runway holding position markings whenever they intersect a runway. Taxiway edge markings are present whenever there is a need to separate the taxiway from a pavement that is not intended for aircraft use or to delineate the edge of the taxiway. Taxiways may also have shoulder markings and holding position markings for Instrument Landing System (ILS) critical areas and taxiway/taxiway intersection markings.

Normal Centreline

The taxiway centreline is a single continuous yellow line, 6 inches (15 cm) to 12 inches (30 cm) in width. This provides a visual cue to permit taxiing along a designated path. Ideally, the aircraft should be kept centred over this line during taxi. However, being centred on the taxiway centreline does not guarantee wingtip clearance with other aircraft or other objects.

Enhanced Centreline

At some airports, mostly larger commercial service airports, an enhanced taxiway centreline will be used. The enhanced taxiway centreline marking consists of a parallel line of yellow dashes on either side of the normal taxiway centreline. The taxiway centrelines are enhanced for a maximum of 150 feet prior to a runway holding position marking. The purpose of this enhancement is to warn the pilot that they are approaching a runway holding position marking and should prepare to stop unless they have been cleared onto or across the runway by ATC.

Taxiway Edge Markings

Taxiway edge markings are used to define the edge of the taxiway. They are primarily used when the taxiway edge does not correspond with the edge of the pavement. There are two types of markings depending on whether the aircraft is supposed to cross the taxiway edge:

• Continuous Markings: These consist of a continuous double yellow line, with each line being at least 6 inches (15 cm) in width spaced 6 inches (15 cm) apart. They are used to define the taxiway edge from the shoulder or some other abutting paved surface not intended for use by aircraft.
• Dashed Markings: These markings are used when there is an operational need to define the edge of a taxiway or taxilane on a paved surface where the adjoining pavement to the taxiway edge is intended for use by aircraft (for example, an apron). Dashed taxiway edge markings consist of a broken double yellow line, with each line being at least 6 inches (15 cm) in width, spaced 6 inches (15 cm) apart (edge to edge). These lines are 15 feet (4.5 m) in length with 25-foot (7.5 m) gaps.

Taxi Shoulder Markings

Taxiways, holding bays, and aprons are sometimes provided with paved shoulders to prevent blast and water erosion. Although shoulders may have the appearance of full-strength pavement, they are not intended for use by aircraft and may be unable to support an aircraft. Usually, the taxiway edge marking will define this area. Where conditions exist such as islands or taxiway curves that may cause confusion as to which side of the edge stripe is for use by aircraft, taxiway shoulder markings may be used to indicate the pavement is unusable. Taxiway shoulder markings are yellow.

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