The sign "Mandatory passing on the right" indicates that vehicles must pass other vehicles on the right side only. This typically applies in situations where there are multiple lanes or when overtaking is permitted. Drivers are required to keep the left lane clear for faster-moving traffic or for vehicles that are overtaking. It is essential to adhere to this rule to ensure safety and smooth traffic flow, as failing to do so can lead to accidents or traffic violations. Always be cautious and ensure that the lane you are moving into is clear before changing lanes or overtaking. If you have any further questions about this sign or related traffic rules, feel free to ask!