The developed world's most hostile city for cycling title has been earned by Sydney, Australia.
US academic John Pucher, who spent a sabbatical year researching ways to boost bike-riding levels in the city, revealed his efforts to ride to Sydney University from his Stanmore home.
"I did not cycle that often because I almost got killed several times - people cutting me off, squeezing me off the road and not stopping," the Sydney Morning Herald quoted him as saying.
"Whether I was a pedestrian or cyclist I found the level of the hostility of enough Sydney motorists worse than I had seen anywhere in the world," he revealed.
For decades Dr Pucher, from Rutgers University in New Jersey, has been riding bikes - from the cycling wonderlands of Amsterdam and Copenhagen to the car-choked streets of many US cities.
But he was left stunned by his experience in Sydney.
"In Texas or in the south-east of the US it's aggressive but there was an incredible level of aggression from Sydney motorists ... It's not every motorist but there were enough of them, whether it was resentment, irritability or just aggression, I don't know," he said.
In a paper to be published in the Journal of Transport Geography, Dr Pucher and two Australian colleagues explain why Sydney cycling levels lag much of the developed world.
Their paper compares cycling in Sydney and Melbourne and finds twice as many trips are made by bicycle in Melbourne as Sydney with the rate of trips in Melbourne growing at three times that of Sydney.
Dr Pucher says Melbourne's flatter terrain and lower rainfall alone do not explain why in hilly San Francisco the percentage of trips by bike has grown to 2.5 per cent, 31/2 times Sydney's rate of 0.7 per cent.
More significant than topography is reducing aggression among motorists. Making cyclists, especially female cyclists, feel safer, is a job Melbourne has done much better than Sydney.
Dr Pucher says women are a litmus test for cycling safety as many will ride only if they feel safe.
Twenty-five per cent of commuting cyclists in Melbourne are women, but only 17 per cent in Sydney. In Denmark the figure is 45 per cent and in the Netherlands 55 per cent.
Still, he was impressed with the City of Sydney spending 76 million dollars on a 200-kilometre network of bike lanes.
The Premier, Kristina Keneally, says that since she took up riding to work more than a year ago she has never had an incident.
"I see some drivers perhaps not being as aware of cyclists as they could be. That said, there are cyclists who take risks that I wouldn't," she stated.