Opponents of plans to build a second road tunnel through the Gotthard in central Switzerland - a major transalpine thoroughfare in Europe - have gathered enough signatures from the public to force a referendum on the issue.
Parliament had approved the estimated CHF2.7 billion ($2.8 billion) project to build a second tunnel and renovate the existing one in September.
Supporters, mainly the centre-right and right of the political spectrum, had argued that the move was in the interest of road safety, was economically and environmentally sustainable, and a sign of solidarity to the Gotthard region.
But those against were worried that the second route would lead to additional traffic and environmental problems, be too costly to build and breach a constitutional amendment to put transalpine road traffic onto rail.
Afterwards environmental groups, including the Alpine Initiative and the Swiss branches of the WWF and Greenpeace, pledged to challenge the parliamentary decision in a referendum.
Lots of signatures
On Friday the “no to the second Gotthard tunnel”external link group announced that they had already collected more than 100,000 signatures - 50,000 are needed to force a referendum challenge according to Switzerland’s system of direct democracy - a month before the deadline for collection.
“We are very happy that we have managed to sort out the referendum this well and so quickly,” said Caroline Beglinger, co-president of the referendum committee, in a statement.
In all, 50 local national, local and regional groups are campaigning against the second road tunnel, including the Social Democrats, Green and Liberal Green political parties.
A vote could take place as earlier as June 2015. It would be the third time since 1994 that the Swiss have directly or indirectly voted on the issue of a second tunnel. Until now they have always rejected the move.
The second tunnel project was due to start in 2020 and take seven years to complete. After that the existing tunnel, which was built in 1980, was to be renovated. Both tunnels were expected to be in operation from 2030.
swissinfo.ch and agencies