A study of a shared bicycle scheme has found riders travel faster on Wednesdays than other weekdays, and average speeds greater than cars in peak hour traffic.
Since the shared bicycle scheme was introduced in the French city of Lyon in 2005, the number of bicycles on the road has doubled.
In the past few years, shared bicycle schemes have been set up in many European and UK cities, as well as in Melbourne and Brisbane. Local government planners in Sydney are considering a similar scheme, which is expected to start in 2011.
The schemes make bicycles available in 'pods' throughout the city centre which anyone can use for a trip across town at little or no cost. The bicycle is then returned to the pod for others to use.
The bicycles in Lyon are fitted with onboard computers and accessed via smartcards. Between May 2005 and Dec 2007, data was collected from 11.6 million bicycle trips.
The study by Pablo Jensen and colleagues at the École Normale Supérieure de Lyon and published on the pre-press website arXiv.org, found during peak hour in the city, bicycles travelled about 15 kilometres per hour - up to 50% faster than cars.
Travel time for cars would be even slower, they say, if the time taken searching for a parking space was taken into account.
Perception cars are quicker
"What's interesting is that drivers do tend to underestimate how long it will take to get to a place by car, and overestimate how long it will take to get there by bicycle," says Elliot Fishman, director of the Institute for Sensible Transport in Melbourne.
"There's a perception that the car is fast and convenient, whereas a bicycle is only used if you don't have the means to travel by car.
"But what a lot of new cyclists say is how surprised they were at how quick it was to get to work."
He says the study found that bicycles tend to take the same routes as pedestrians, rather than cars, making use of footpaths, going the wrong way up one way streets and using bus lanes.
"Short cuts make a huge difference to the speed of bicycles … What we've seen internationally is that where planners have tried to maximise the accessibility of bicycle routes, there are much higher level of bicycle use compared with cities where the routes for bicycles and cars is the same."
Short cuts for bicycles might include paths through parks, pedestrian and bicycle bridges over waterways, and access for bicycles and walkers through dead end streets.
These measures counteract the slower speed of bicycles by making the travel distance shorter, Fishman says.
Social factors affect usage
Intriguingly, the study also found that bicycles travelled fastest on Wednesday mornings. This may be due, the authors say, to the fact that many women in France take Wednesdays off to look after children, leaving a higher proportion of male riders on the road.
"It would be interesting to replicate the study in Australia to see what social patterns were revealed in our transport behaviour," says Elaena Gardner, president of bicycleSydney.
For instance, she says, there's a difference between morning and afternoon peak times for bicycle use in Sydney, perhaps indicating more commuters leaving work after 7 pm.
"There is a general concern that any bicycle share scheme in Australia will suffer from our mandatory helmet legislation … having to bring a helmet does not make the share scheme convenient," she says.
Fishman says being required to wear a helmet is like "opening up a pub and then asking everybody to bring their own glasses".
"When people are leaving home at 7.30 am they are not thinking they'll use a bicycle share in the middle of the day, so they are not taking a helmet."