Tronchetto is an artificial island on the far western tip of Venice, created in the 1960s and linked to the bridge that connects the city to the mainland. It has the city's wholesale market, Trochetto Mercato.
Like Piazzale Roma, it has parking garages, and is linked to Piazzale Roma and the Marittima ferry/cruise boat terminal by the mass transit Venice People Mover. It's also the ferry terminal for those taking a car to the Lido and Cavallino-Treporti.
Tronchetto car park website