Take the A91 (E80 motorway for Fiumicino), then take the A90. Continue until the beltway where you have to take the A1 (E35 for North Rome). Continue along the "Autostrada del Sole" and exit at Florence-Certosa. At the roundabout take the first exit towards Colle Val d'Elsa, Siena. Exit at Tavernelle, turn on the left, then on the right and again on the right in via Palazzuolo. Once in Barberino Val d'Elsa, follow directions for Petrognano.