Experts have detonated a rock hanging precariously over the main north-south road axis in the Swiss Alps.
But it will be several more days before the motorway leading to the Gotthard road tunnel will be reopened after a rockslide at the end of May.
Some 1.5 tons of explosives were used on Friday to blast away 5,500m3 of loose rock above the motorway near the village of Gurtnellen in central Switzerland.
The authorities said the detonation had gone as planned and that trees prevented any big rocks from hitting the road. It will take several days to clear the debris.
Several hundred people watched the blast, which was broadcast live on public television. Train services had to be suspended and all roads in the region were sealed off for several hours. The authorities also evacuated more than 30 people from their homes for safety reasons.
Officials said they hoped to give the all-clear next week for the expected wave of holiday makers passing through Switzerland from northern Europe to Italy and back.
An estimated 50,000 cars a day pass through the Gotthard tunnel during the summer holiday season.
The road was closed following a rockslide in May in which two people were killed by huge boulders.
As a result, road traffic had to be diverted mainly over the San Bernardino pass in the southeast of the country, leading to long traffic jams in the region.
Road hauliers have repeatedly called for transport restrictions to be eased, including the lifting of a night-time ban. Local authorities and businesses have pointed out the local economy has suffered a noticeable slowdown during the closure.
However, the transalpine rail link through central Switzerland has remained open over the past few weeks. The Federal Railways has laid on extra trains to cope with the increased demand.
swissinfo with agencies
The 17km Gotthard road tunnel was built in 1980 linking the southern Ticino region and central Switzerland.
The 15km first Gotthard rail tunnel between Göschenen and Airolo was the world's longest tunnel when it was opened in 1882. It runs underneath the St Gotthard pass.
A second 57km rail tunnel is expected to be operational in 2015.
On weekdays about 10,000 vehicles pass through the Gotthard road tunnel.
Up to 13,000 vehicles a day use the tunnel during normal weekends.
Six million cars transit through central Switzerland over the main transalpine road axis each year.