The number of motorcycles in many Latin American cities, such as São Paulo, Rio de Janeiro, Brasilia and Bogotá, has grown much faster than the automobile fleet in recent years. In many Asian cities, motorcycles and three-wheeled vehicles are the primary modes on urban roads.
Motorcycles are prevalent in the developing world, because they are relatively cheap to own and operate, usually less regulated (in terms of licensing, enforcement, and insurance), and can be faster than other modes on very congested roads -- by swerving and bypassing other vehicles.
These vehicles are also a lot less safe than conventional ‘four-wheelers’ for the same reasons and are statistically more likely to be involved in serious accidents because of, among other reasons, the physical vulnerability of the driver and passenger. See a video report  from Brasilia (in Portuguese).
Motorcycles certainly provide improved mobility to those willing to brave personal risks, but there are additional costs borne by others.
In São Paulo, there are multiple daily reports of motorcycle commuters and couriers (known as “moto-boys,” delivering everything from packages to pizzas) dying in traffic and causing a great deal of traffic disruption. In response to this, São Paulo has begun testing motorcycle-only lanes on two main arteries and restricting motorcycles on many other roads. It is not clear whether this strategy will work or be enough, but the problem is large enough to have created incentives for experimentation.
In some Chinese cities, motorcycles have been banned altogether from the city center, so less-potent but cleaner electric bicycles are more common. What else can be done and what are some good examples?
There is also the question of how motorcycles compete with public transport modes as incomes rise in developing countries and residents require greater mobility to access jobs and services. The commuter without a vehicle, who is the primary customer of public transport, may find it more convenient to use a motorcycle as soon as he is able to afford it – particularly when the public transport system is not competitive. This phenomenon may have serious implications on the sustainability of public transport systems, the environmental and social impact of the transport sector, and the eventual development of cities.
Photos: Sam Zimmerman