How many threshold stripes are there on a runway that is 18 m wide?

To determine the number of threshold stripes on a runway that is 18 meters wide, it's important to consider the standard specifications for runway markings set by relevant aviation authorities.

Typically, each threshold stripe is 0.5 meters wide and 3 meters long, and they are placed parallel to the runway centerline. To calculate the number of stripes, you can divide the total width of the runway by the width of each stripe. In this case, with an 18-meter wide runway, you would find that the number of stripes is calculated as follows:

[ \text{Number of stripes} = \frac{\text{Width of runway}}{\text{Width of each stripe}} ]

[ \text{Number of stripes} = \frac{18 \text{ m}}{0.5 \text{ m}} = 36 \text{ stripes} ]

However, the relevant dimensions for runway threshold markings might restrict how many stripes are actually used and visible on the runway. According to standard practices and regulations, a runway would typically display up to 4 threshold stripes, which are sufficient for identifying the threshold for aircraft landing.

Therefore, recognizing that the maximum practical number of threshold stripes for an 18 meter wide runway is indeed 4