However, countries with helmet laws could lose out on the benefits from the City Bike revolution. None of the present schemes requires cyclists to use a helmet and none are provided. As well as the practical difficulties of offering helmets to users at each bike station in a sufficient range of sizes, there are health and hygiene issues that make sharing helmets unacceptable.
Head lice can live two days away from a host and are endemic in the western world, especially among children. Fungal scalp infections (“tinea capitis”) spread by contact. They are usually caused by fungi of the genera Microsporum and Trichophyton. They may be serious (“kerion”) and can result in hair loss (alopecia) or even major skin loss. Then there are the less tangible but real fears people have about not wanting to wear an item of second hand clothing, especially one that has not been washed. Helmets left for days exposed to the elements could grow mould, especially in humid climates.
Just as important, City Bike schemes are the most successful if they are able to capture impromptu journeys on demand, with no pre-planning and the minimum of fuss for the client. The need to carry a helmet around just in case you will want to hire a bike, or to have to mess about adjusting a hired helmet to fit, would kill off a large part of the market.