What is the primary guideline for numbering runways?

Runways are numbered using the nearest compass bearing, which reflects their orientation on the compass. Each runway is assigned a number that corresponds to one-tenth of its magnetic azimuth rounded to the nearest whole number. For example, a runway aligned approximately with 90 degrees east is designated as runway 09, while one aligned with 270 degrees west would be runway 27. This system allows pilots to quickly ascertain the orientation of the runway in relation to their approach angle, facilitating safer and more efficient navigation during takeoff and landing. Understanding that the primary factor for runway numbering is based on compass bearings helps reinforce the importance of geographical orientation in aviation operations.

The other options do not capture the primary rationale for runway numbering, as aircraft models, geographic location, and annual traffic volume are not standard criteria used in the system.