Lumia serves Agrigento (€6.50, 1½ hours, 11 daily Monday to Saturday, one Sunday) and Trapani (€9, 2¼ hours, three Monday to Saturday, one Sunday). All buses arrive at the bus stop by the Villa Comunale on Via Figuli and leave nearby from Via Agatocle. Schedules and departure times are also displayed there. Buy your tickets at L'Antico Chiosco on Piazza Friscia.
Sciacca is about 65km from Agrigento along the SS115. There's parking on Via Agatocle near the Nuovo Stabilimento Termale, and on Piazza M Rossi, adjacent to Piazza Scandaliato.