Cassandra Devine was riding along Flinders Street when a door flew open, throwing her from her bike.
She did not break any bones but it shook her confidence - and changed her riding habits.
She now makes a priority of looking for the safest route.
Bicycle tracks on La Trobe st are becoming very popular, especially with female cyclists. Photo: Justin McManus
''Particularly since it happened, I have been much more aware generally, and much more aware of riding in a designated bike area,'' Ms Devine said.
Among women, she is not alone.
Preliminary results from a bicycle survey on Tuesday morning found women were choosing the city's safest routes into the CBD, including the segregated lane on La Trobe Street, where there was a 30 per cent increase in the number of female riders.
The count, by the Bicycle Network, found routes judged ''safer'' were more popular with women than men.
They favoured Napier Street in North Fitzroy, Rathdowne and Canning streets in North Carlton and the Upfield rail line bike path.
''It's impossible to ignore the conclusion that a sure way to increase the numbers of riders in Melbourne is to make the network safe and attractive to women - wherever good routes are created they take to them instantly,'' spokesman Garry Brennan said.
He said there were more men than women on routes south of the city, where they were generally less safe.
Bicycle Network grades routes by degrees: from no interaction with cars at one extreme to ''too narrow'' bicycle lanes on St Kilda Road, where men were found to outnumber women three-to-one.
The count found key routes into the city carried between 600 and 1000 riders an hour during peak times. Mr Brennan said Docklands office workers were using bikes in greater numbers.
Melbourne City Council has launched a campaign to help reduce fatalities and serious accidents by 20 per cent over five years. Lord mayor Robert Doyle said there were four road deaths, 236 serious accidents and 846 other accidents in the city in 2012. Most involved pedestrians and cyclists, he said.
''You can put up signs and you can levy fines, but in the end you need to change people's behaviour,'' Cr Doyle said.
The campaign includes warning pedestrians to ensure they are alert and not distracted by smart phones or MP3 players.
The council will run the program until June at hot spots, including Collins Street and St Kilda Road, where drivers will be warned about the risk of ''dooring'' and being distracted behind the wheel.