This working paper by Richard B Ellison and Stephen Greaves, Institute of Transport and Logistic Studies, University of Sydney was released in March 2011. The analysis suggests that around 20 percent of people could switch totally from cars to bicycles without incurring more than a 20 minute additional increase in travel time on average per day.

A key issue for both sustainable transport and public health is the viability of cycling as a genuine alternative to the car, particularly for short trips. This paper considers this issue by assessing hypothetically the travel time implications of substituting actual car trips with cycling. The car trips are captured over several weeks for 178 Sydney motorists using GPS technology, while the cycling trips are generated using reverse geocoding processes in GIS software, taking into account the impacts of terrain in particular on cycling travel times. Both individual trips and more importantly trip chains are considered. Assuming an ‘inexperienced adult’ cyclist, results suggest that over 90 percent of car trips up to five kilometres in length (which comprise 58 percent of trips), could be cycled within 10 minutes of the time taken by car, a similar finding to results reported elsewhere.
As the level of cycling experience increases, the ‘bikeable’ distance increases with the majority of ‘commuter adults’ being able to cycle the median commuting distance in Sydney of 11 kilometres with little additional travel time compared to a car. When considering trip chains, while the competitiveness of cycling goes down as more legs are included, the total distance of the chain emerges as a more crucial issue with cycling being equally competitive for trip chains shorter than 10 kilometres as for individual trips shorter than 10 kilometres. Finally, when considered in the context of daily travel time budgets, the analysis suggests around 20 percent of people could switch totally from cars to bicycles without incurring more than a 20 minute additional increase in travel time on average per day.
Travel time competitiveness of cycling in Sydney | 373 Kb PDF