The sign you are referring to is known as the Distance sign on highway-type two-lane roads execution according to RWB-1. This sign is typically used to indicate the distance to the next exit or junction on a highway where there are two lanes for traffic.

The main purpose of this sign is to inform drivers about the distance they need to travel before they can exit the highway. It helps drivers plan their maneuvers, ensuring they have enough time to prepare for the upcoming exit. The sign is an essential tool for maintaining safe traffic flow and preventing abrupt lane changes.

Understanding this sign is crucial for your driving test and for safe driving in general. Always pay attention to such distance indications, as they guide your driving decisions on highways. If you have any specific questions about using this sign or other traffic rules, feel free to ask!