Bologna is a well-connected city, easy to reach by plane, car, or train. Given its moderate size of about half a million people, it does not have the traffic and clutter of Milan or Rome.
By train. The central train station is located to the north of the city centre and from the station Via Indipendenza brings you to the main square, Piazza Maggiore, in about 20 minutes on foot. Bologna is a major rail hub. To Milan (2.5 hrs) or Florence (1.5 hrs) you can take many convenient regional trains. For Rome, it is worthwhile taking a high-speed train which gets you there in about 2.5 hours.
Remember that in Italy you must validate your ticket in one of the machines before boarding regional trains, otherwise you risk a fine. High-speed trains (Frecciarossa, Italo) require a reservation and don't need validation.
By plane. Bologna has a convenient airport, Aeroporto G. Marconi di Bologna, to the northwest of the city with frequent flights to all major European destinations. It is connected to the city centre and train station by the Aerobus, which runs every 20 minutes and takes about twenty minutes. Other airports within reach include Rimini, Verona, and Florence.
By car. Bologna is conveniently located on the A1, the major highway that runs north-south through Italy. From the south (Rome, Florence), take the exit Bologna-Casalecchio to get on the Tangenziale and follow the signs for the centre. From Ravenna or Ancona on the A14, take the exit at Bologna-San Lazzaro.