PINEROLO, Italy -- Edvald Boasson Hagen of Norway won the 17th stage of the Tour de France on Wednesday, the first of three days in the Alps, while Thomas Voeckler retained the yellow jersey but lost time after riding off course on the final descent.
Defending champion Alberto Contador made repeated attempts to get away from his rivals, but was caught on each occasion. He finished in the same time as Cadel Evans, the Schleck brothers and Samuel Sanchez.
Voeckler lost 27 seconds and is 1 minute, 18 seconds ahead of Evans. The 2010 Giro d'Italia champion Ivan Basso also lost time.
Boasson Hagen completed the 111 miles across the Alps from Gap to the Italian town of Pinerolo in 4 hours, 18 minutes. Bauke Mollema of the Netherlands was second, 40 seconds back, with Sandy Casar of France winning the sprint for third.
Voeckler went too fast on a hairpin turn, skidded onto the shoulder of the forested Alpine road, then raced back to try to catch Contador and Sanchez after they sped by.
"It's a pity, because I saw that Contador, Evans and the Schlecks finished together. If I'd taken fewer risks, I would have finished with them," he said.
The high-speed pursuit led to another mishap in which he jumped a curb, rolled into a small car park and almost crashed.
"It was a fraction of a second, but it seemed like an eternity. I closed my eyes and lifted the front wheel and when I opened my eyes, I was still on the bike," Voeckler said. "So I said, 'OK, here we go: U-turn and back to the race."
Contador was not downhearted by his failure to get away.
"I felt good, and you've got to try," he said. He didn't want to talk about the stages to come.
Boasson Hagen recorded his second stage win and the fourth overall for Norway in this year's race.
"It was very difficult yesterday, and today I was able to do better," Boasson Hagen said. "I felt I was capable of attacking on the last climb."
Mollema was second after Frenchman Jonathan Hivert crashed on the perilous final descent of the Pramartino. Hivert got back on his bike and came in ninth.
Boasson Hagen praised the large contingent of Norwegian fans that has been supporting him and Hushovd throughout the race.
"It's really great to see all the Norwegian flags and Norwegian people around the course. It gives some extra power."
Evans becomes more of a favorite for the title with every day he keeps his advantage of nearly two minutes over Contador.
"With shadows and stuff it was real hard to see. Voeckler ran off the road in front of me -- twice I think. It makes you take things more cautiously. You don't ever want to lose time to anyone," the Australian said. "I've got a good advantage over Alberto now, but Alberto has shown in years gone by what he can do when he's really at his top."
Britain's Mark Cavendish came in 166th of the 169 finishers, more than 14 minutes behind Boasson Hagen, but still held on to the green jersey for the best sprinter after four victories in the flat stages. Six of his HTC-Columbia teammates nursed him through to the end.
The second of the three Alpine stages on Thursday contains three climbs that are so steep they aren't even given a category. It ends with the 14.2-mile climb of the famed Col du Galibier. The full stage is 125 miles, starting at Pinerolo.
Also Wednesday, Russian team Katusha confirmed that rider Alexandr Kolobnev's backup sample tested positive for a banned masking agent.
Kolobnev became the first rider in this year's Tour to fail a doping control when his urine sample taken after the fifth stage had traces of hydrochlorothiazide, a diuretic that can hide the presence of other drugs.
Kolobnev was in 69th place when he left the race before the 10th stage.
Katusha said Kolobnev is suspended until the Russian cycling federation holds a disciplinary hearing. He faces a two-year suspension.
Kolobnev was given the bronze medal in the 2008 Beijing Olympics road race after the original bronze medalist, Davide Rebellin of Italy, was found guilty of doping.
Associated Press Writer Jamey Keaten in Pinerolo, AP Sports Writer Graham Dunbar in Geneva contributed to this report.