Det är syftet med poängmärket, brittisk stil. UK AIP GEN 1.7 ( 2018-8) noterar följande skäl till den olika märkningen:
- The shape of the marking means that 1/3rd of it is outside the centre 3rd of the runway and is therefore less prone to rubber contamination.
- The marking is more easily identifiable as it differs from the TDZ markings.
- It provides enhanced visual cues for the angle of approach.