Passing lane, commonly known as the left lane, is an important part of the highway system for drivers who need to overtake slow-moving vehicles. However, the phrase passing lane is not universal. Other synonyms can be used depending on location or country. In the UK, the passing lane is called the overtaking lane. In Australia, it is known as the fast lane. In South Africa, it is referred to as the fast lane or outside lane. The term fast lane is also used in some parts of the US. Additionally, in some areas, it may be called the hammer lane or the speed lane. Regardless of its name, the passing lane serves as an essential aspect of road safety and traffic flow.