Buses are the most common vehicles in large cities. They work well on small routes in densely populated areas and are also good for long routes to far-away housing areas. As a rule of thumb, the more capacity a bus has, the lower the average speed will be. Buses can be used to feed other lines with a better capacity, or to easily and cheaply include isolated parts of the city in the public transport network.
Trams operate on rails. They are environmentally friendly, rather fast, and have a good capacity; also, with a good rail system, they can easily avoid getting stuck in traffic. Trams are an essential part of any European city's infrastructure and are usually very profitable as well.
Metro routes can be built on ground level, above ground, and on three underground levels. Metro routes are essential to moving large masses of people while maintaining low operational costs. While metro infrastructure is fairly expensive to build, it's cheap to run and attracts large amounts of passengers. Metro is best used to connect major suburbs to the center of the city.
Many European cities have internal waterways or are located on the coast, making water transport a good choice, especially during the early decades of transportation history. Water buses are good for transporting masses of people, but are rather slow.
Helicopters appeal most to tourists who want a better view of the city and busy business people for whom price is not an issue. Generally, helicopters are expensive and have a really low capacity, but they are quite versatile and fast. A helicopter never gets stuck in a traffic jam!
Stops and Stations
Many different stops and stations are available to cater to the needs of your customers. Some stations are more attractive to passengers, but these usually have higher maintenance costs. You should carefully choose which stops to use, because in low-population areas, the more expensive stops may take a toll on your profits.