The government is facing renewed calls to speed up plans for a reservation system for heavy-goods trucks transiting the Swiss Alps.
The Alpine Initiative group says it is possible to reduce the number of transiting trucks to one million by 2011.
The non-governmental organisation aims to protect the environment from road traffic and promote rail transport. But a look back over the past 15 years leaves top representatives of the group with a feeling of ambiguity.
"We have achieved a number of things," said Fabio Pedrina, president of the Alpine Initiative, at a news conference on Tuesday.
Holding up a glass of water to underline his message, he added: "I'm pleased the glass is half full, but I don't like to see that it is still half empty."
The NGO not only won a nationwide vote in 1994 calling for goods transport to be taken off the road and put on rail. It was also instrumental in bringing down plans for a second road tunnel through the Gotthard in central Switzerland.
However, the group has had little success in implementing a policy to halve the number of trucks transiting the country within a decade.
Parliament last year voted to delay the target date until 2018-2019.
As a start it approved in principle a proposal to introduce a scheme where haulage companies would bid for the rights to use alpine routes, known as Alpine Crossing Exchange.
Pedrina warned the country's transport policy risked falling behind schedule if the government failed to put into practice a series of measures soon.
"We want a swift introduction of the Alpine Crossing Exchange, including negotiations with other European countries."
He also called for steps to boost the capacities of the railways through the Gotthard.
"We hope for higher subsidies for cargo traffic and financial measures to reduce bottlenecks on the rail network as part of government plans to support the slowing economy," added Alf Arnold, the group's managing director.
He stressed the importance of close cooperation with other environmental NGOs in other countries.
Both Pedrina and Arnold refuted allegations that the group had lost its edge over the past few years.
The focus of activities has been re-adjusted and cross-border contacts with groups in Austria and France had become important in an effort to reduce heavy-goods road traffic.
"It does not mean that we will accept another delay in implementing reduction target. A blockade of transiting alpine traffic is still an option," said Pedrina.
Gérard Leras of the French Rhône-Alpes regional council confirmed that the Alpine Crossing Exchange was an absolute must.
"We fully support the Swiss transport policy. Unfortunately we lag behind in France," he told journalists.
For its part, Switzerland's road hauliers' association, Astag, reiterated its opposition to the reservation system.
"Quotas for road transport are nothing other than command-style economy," the association said in a statement.
Astag denounced the government's transport policy as coercive measures that put jobs at risk.
"The policy is a shambles. International freight traffic on roads has seen an above-average increase."
Currently about 1.3 million trucks per year pass through the Swiss Alps, twice as many as the government forecast ten years ago.
swissinfo, Urs Geiser
Swiss transport policy calls for most goods transport to be taken off the road and put on trains.
The number of trucks transiting Switzerland is supposed to drop to 650,000 by 2018-2019 (one million in 2011).
Last year parliament decided to delay the initial target date of 2009 by ten years.
Presently about 1.3 million trucks per year pass through the Swiss Alps.
The Gotthard is on the main north-south artery through Switzerland. There are two other routes: through the Lötschberg-Simplon tunnels in the west of the country as well as the San Bernardino in eastern Switzerland.
The Alpine Initiative group was founded in 1987 and claims to have about 50,00 members and supporters.
It aims to protect the alpine environment from increasing road traffic.
The non-governmental organisation forced a nationwide vote on the issue, which was approved by the Swiss voters in 1994.
As a result, parliament and the government decided to introduce fees for heavy-goods vehicles, increasing the maximum weight of trucks from 28-40 tons and subsidising tickets for trucks which use rail transport.
The group also helped defeat a proposal in 2004 to build a second road tunnel through the Gotthard in central Switzerland.