The government has refused to relax restrictions on traffic using the Gotthard tunnel, despite intense pressure from motoring groups during a roundtable discussion.
Drivers and road hauliers associations said they were disappointed by the outcome of the talks held on Thursday. They renewed calls for the government to abandon the alternating one-way system for trucks through the Gotthard, saying it had caused chaos on the main transalpine route through central Switzerland.
The Swiss transport minister, Moritz Leuenberger, did not yield to calls to scrap the system, but he said he hoped to ease congestion by alternating one-way traffic every two, rather than every three hours.
In addition, Leuenberger said freight trucks without heavy trailers would be allowed to use the Gotthard pass instead of the tunnel.
The one-way system was introduced last December after a disaster in the tunnel. A fire erupted following a head-on collision between two trucks; 11 people died.
Prior to Thursday's meeting, Rudolph Zumbühl, head of economic affairs at the motoring association, the Touring Club of Switzerland (TCS), said the chronic congestion caused by the one-way system was not sustainable long-term.
"There are about 20,000 people using the tunnel every day, and the current situation is very problematic for them," Zunbühl told swissinfo. "There is no infrastructure to cope with the high number of stationary lorries that are waiting to enter the tunnel, which also pose a safety risk."
The government last month defended the restrictions, saying the current limit of 3,500 trucks per day was introduced to smooth traffic on the main motorway, and for the customs authorities at the borders to Germany and Italy respectively.
Rail ferry wins support
Leuenberger said all participating parties at the talks had supported the government's long-term plans to build a rail ferry for freight transport through the tunnel.
He also said a second meeting before the summer holidays would discuss a proposal that required truck drivers to book their journey through the tunnel in advance.
A survey of European tunnel safety has described conditions in the Gotthard tunnel as "adequate". The survey, jointly conducted by 14 European motoring associations, said safety installations were of a high-level, but that problems persisted because of excessive traffic.
"There's a lot of noise and too much congestion inside the tunnel," Erich Schwizer, a spokesman for TCS, which took part in the survey, told swissinfo. "Long-term, the only really safe solution is to build a second tube in the tunnel so that cars don't have to circulate alongside buses and trucks."
Schwizer said a new ventilation system, to be build later this year, would further improve the Gotthard's safety ranking.
swissinfo with agencies