Construction on a second, parallel road tunnel was started. In first instance it was only built for safety: an escape route in case of accidents. This second tunnel can be built out to a full road tunnel, allowing four lanes of traffic. Efforts to do this have failed, blocked by political resistance. The Alpine Initiative for the protection of the Alpine region from transit traffic, which raised barriers against road tunnel construction, was initially blocked by the Swiss Parliament. A February 1994 Alpine Initiative passed (with 52% of the vote), and Parliament upheld the referendum twice through the 1990s. The pro-tunnel Avanti Initiative brought a referendum to voters in February 2004, which was rejected (by 62.8%).