Swiss Transport Minister Moritz Leuenberger has said steps to cut down on alpine traffic will only be effective if coupled with greater cooperation by other nations.
He was responding to renewed calls on Saturday by the Alpine Initiative pressure group for the government to introduce a reservation system for lorries transiting the Alps.
"Only a coordinated introduction [of a system] across the Alps has a chance of success," said Leuenberger, addressing an event for the 20th anniversary of the founding of the Alpine Initiative group.
He paid tribute to the group's "constructive collaboration", notably in holding talks with the European Union over land transport.
A reservation system is one of different ideas being studied to cut down on environmental problems arising from alpine traffic.
Leuenberger told the SonntagZeitung newspaper that a pilot project was expected to be introduced by 2011.
The event in Flüelen also marked the 15-year anniversary of the successful nationwide vote instigated by the group, aimed at protecting the alpine environment from increasing road traffic.
Group president Fabio Pedrina said despite a yes result in the vote, the measures were still only partly enshrined in law.
The non-governmental organisation says rail transport needs to be promoted and says it is possible to reduce the number of transiting trucks to one million by 2011. It claims to have about 50,000 members and supporters.
swissinfo.ch with agencies
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