The referendum covers a series of national, regional and local issues including the suggestion for the new route across the lake, which is known as Lac Léman in French. The proposal does not specify whether the crossing would be a bridge or a tunnel.
Building the link would enable completion of a motorway ring-road around the city. The crossing, which could be built under a public-private partnership, has the backing of the state and local councils.
Cost of the scheme has been put at US$2.77bn to US$3.29bn.