The detail that "on a bike, Jourdan's commute lasts one hour" might be a contrast and contradiction in the context of the benefits of cycling.
This detail could be seen as a contrast to the perceived time-saving benefits of cycling, as it suggests that Jourdan's commute takes a significant amount of time despite using a bike.
It could also be a contradiction to the idea that cycling is always a fast and efficient mode of transportation.
This detail may highlight the potential challenges and variability of cycling as a mode of transportation, contrasting with the common perception of it being a quick and easy way to commute