The death of a cyclist knocked down by an official Olympic bus is the 10th fatality involving bikes in London this year.
The driver has been bailed pending further inquiries after the 28-year-old died on Wednesday night after being hit by a bus ferrying journalists between Olympic venues.
A Metropolitan Police spokesman said a man in his mid-60s was arrested at the scene, just outside the Olympic Park in Stratford, east London, at 9.28pm on suspicion of causing death by dangerous driving.
The victim was struck by the double-decker just after 7.30pm. He was not believed to be an athlete, and is expected to be formally identified later.
A Metropolitan Police spokesman said the man was pronounced dead at the scene in Ruckholt Road, at the junction with the A12.
Safety campaigners said it was the 10th cyclist to die in London since January, the same number as in the whole of 2010. At this rate, the number of cyclists killed on London's roads will exceed last year's death toll of 16, campaign groups fear.
Olympic gold medal-winning cyclist Bradley Wiggins said he would like to see the introduction of a law making it compulsory to wear cycling helmets.
"It's dangerous and London is a busy city and has a lot of traffic," he said. "I think we have to help ourselves sometimes. I haven't lived in London for 10 to 15 years now and it's got a lot busier since I was riding a bike as a kid round here, and I got knocked off several times."
London Mayor Boris Johnson said there were no plans to require cyclists to wear helmets or to provide them for the capital's fleet of "Boris bikes".
The Mayor was wearing a helmet as he cycled into Whitehall for the latest ministerial Olympics meeting at the Cabinet Office. Asked if other cyclists should be made to wear protective headwear, Mr Johnson said: "I think they should do if they want to."