Public transport vehicles are an important part of many cities' transportation systems. The two most common types of public transport vehicles are buses and trams. Buses, which have three letters in their name, are motorized vehicles that typically run on roads and are used to transport people from one place to another. Trams, which have four letters in their name, are also motorized vehicles, but they typically run on tracks and are used to transport people within a city or town. Both buses and trams are important components of public transportation systems, providing efficient and affordable transportation for people who need it.