Trains from Roma Tiburtina station take just over an hour. They are hourly or more frequent.
Buses serve Tivoli from the Ponte Mammolo metro station on Rome's Line B. The bus also stops near Hadrian's villa.
You can drive from the center of Rome, along the Via Tiburtina. However, this is a slow, ugly road that passes through Rome's unattractive suburbs. A quicker route is to take the Autostrada A24 in the direction of L'Aquila. The exit for Tivoli is soon after the main toll station, where you have to take a ticket. However, you should avoid returning by the same route on a weekend evening, particularly during the ski season, as the toll station can get very congested.