From SKYbrary Wiki
In aviation, Stopway (SWY) is a term related to the dimension of some runways. The stopway is an area beyond the runway which can be used for deceleration in the event of a rejected takeoff. It must be:
- At least as wide as the runway
- Centered upon the runway extended centerline
- Capable of supporting the aeroplane during an aborted takeoff without causing structural damage to the aircraft
- Designated by the airport authorities for use in decelerating the airplane during an aborted takeoff
Stopways are identified by large yellow chevrons on either end of the main runway.
When a stopway exists, the length of the runway plus the length of the stopway equals the Accelerate Stop Distance Available (ASDA)