runway threshold marking

runway threshold marking

Markings placed to indicate longitudinal limits of that portion of the runway usable for landing. They consist of long vertical lines 100 ft (30 m) long and 3 ft (1 m) wide and are placed just short of runway designation markings. They consist either of eight longitudinal stripes of uniform dimensions disposed symmetrically about the runway centerline, or the number of stripes is related to the runway width, as indicated in the illustration. Green lights on either side of the runway indicate the threshold at night or in restricted visibility.