Switzerland's transport and environment minister, Moritz Leuenberger, has told his counterparts from Alpine nations that boosting public transport is the only way to realise an environmentally-friendly transport policy.
Opening the sixth Alpine conference, Leuenberger said on Monday it was also the only way to prevent a breakdown of the road system.
He added that Switzerland alone could not reach its aim of increasing the railways' share of international freight. He said this is where international accords were needed.
The conference, held every two years, brings together the environment ministers of the signatories to the Alpine Convention, which aims to co-ordinate the use and protection of the Alps.
At their two-day meeting in Lucerne, the ministers are expected to sign a transport protocol, which obliges signatories to keep traffic below levels where it would threaten the wellbeing of humans, flora and fauna. It also demands that no new transalpine roads be built.
On Tuesday, Switzerland will also sign another two protocols, covering energy and the settlement of disputes.
So far, Switzerland has signed five of the protocols, covering tourism, the protection of nature, alpine economy, alpine forestry and land management.
The signing of the transport protocol will prove no problem for Switzerland, which has stricter laws on major road development in the mountains than those enshrined in the protocol itself.
But even with the signing of the remaining protocols, there are no guarantees that Switzerland is ready to apply the convention. Parliament has refused to ratify the convention, saying all protocols must be signed first, and there is widespread resistance to some of its provisions in certain mountain cantons.
There is, however, growing pressure, to see the convention applied as soon as possible. The International Commission for the Protection of the Alps (CIPRA) has asked for a heavy-truck tax to be introduced all over Europe.
The organisation, which brings together, among others, the Swiss Transport and Environment Association and the Alps Initiative, also wants road traffic to be reduced and opposes the building of a second tunnel be built under the Gotthard pass.
The Alpine Convention brings together Switzerland, Germany, Austria, France, Italy, Liechtenstein, Monaco and Slovenia.
swissinfo with agencies