Bike-sharing schemes allow people to rent bicycles for short trips, usually by unlocking them with a smartphone app. Early schemes required users to pick up and return bicycles at fixed docking stations. More recently, "dockless" systems have appeared, in which bicycles can be left almost anywhere and located using GPS. Dockless systems grew rapidly in some cities, but they also created problems. Bicycles were left blocking pavements and entrances, and in some cases large numbers were abandoned or damaged. Several operators expanded too quickly and went out of business, leaving local authorities to deal with the unused bicycles. As a result, many cities now require operators to obtain permits and limit the number of bicycles they may place on the streets. Some have created designated parking zones, and users who leave bicycles outside these zones may be charged an extra fee. Where such rules are well designed, bike-sharing can reduce short car journeys and help people reach train and bus stations more easily.

In early bike-sharing schemes, users had to return bicycles to fixed stations.