Corso Vittorio Emanuele, 353
The No Mafia Memorial is located on no-car zone and you can go on foot:
Via Roma/Vucciria stop.
Bus number 101 or 102, then corso Vittorio Emanuele (4 min)
Bus number 104, via Ruggiero Settimo stop (via Mariano Stabile corner), then walk along via Maqueda, when you arrive at Quattro Canti then turn to the right in Corso Vittorio Emanuele (12 min)
Bus number 309, 389 - Indipendenza/Pisani stop, then walk in the Corso Vittorio Emanuele direction (18 min)
The No Mafia Memorial is situated in the Palermo historical centre - no-car zone.
Useful links: How to move in Palermo