Rome has a very good public transport network, since it has developed as a very popular tourist city. The underground has not so many lines like other capital cities do, but buses take you virtually anywhere.
The bus is the main means of transport in Rome. The network is made up of a large number of lines. Unlike other cities, buses are reliable, but tend to be crowded. If not absolutely necessary, you should avoid traveling by bus at rush hours. Buses don’t use lanes separated from other traffic, so you will spend a lot of time in them. It may take up to 15 minutes to get over the traffic jam at Termini station! Night buses are also reliable and useful to get home after a late party.
Tourist buses are very popular. Most of them use the hop on / hop off system. Their route includes most of the attractions, so you may choose one if you don’t have too much time or are too lazy to discover the city by yourself.
There are only two underground lines in the city. The underground is very convenient if you have stations next to your departing point and destination, since it is fast. It may become very crowded at rush hours.
Rome also has a few tram lines. If your route is close to tram stations, you may use these, as they use separate railways and are quite fast.
Tickets can be bought from tobacco shops. Only underground stations have automatic machines or clerks selling tickets. You use the same tickets for underground, bus or tram. There are a lot of options to consider: single journey tickets, regular passes or tourist passes that also include discounts to some attractions. Tickets must be validated in the special machines that will print the boarding time on them.
You can find our more on the public transport in Rome from the official website www.atac.roma.it.