At the Haojue showroom in Kigali, Rwanda’s capital, Gaston Kamo dusts the latest model’s ruby-red fuel tank. “With motorcycles you can go everywhere, even muddy roads,” says the salesman for the Chinese manufacturer. The gleaming 125cc bike costs 1.25m Rwandan francs (around $1,000). “Much less than a car,” adds Mr Kamo, gently angling for his cut.

Cheap bikes from China and India are roaring about Kigali and many other cities. Africa has about 27m registered motorbikes, up from fewer than 5m in 2010, according to a report by the FIA Foundation, a global road-safety charity. Some 80% are used for deliveries or as two-wheel taxis, which are known by various names including okada, and boda boda. They are transforming mobility in Africa.

Behind the rise is a story of supply and demand. Brands from China (such as Haojue) and India (such as Bajaj) are cheap enough for the average African rider. Some have set up assembly plants in countries such as Togo and Angola. Many have done deals with financial firms that offer loans to pay for the wheels. Some are now also selling electric motorcycles.

Africa’s urban population will almost double from 491m in 2015 to 966m in 2035, reckons the UN. Walking across sprawling cities takes ages and, in the absence of pavements, can be dangerous. Motorcycles are cheaper than car taxis (roughly half the price for a trip of the same distance) and often faster. The average car commuter in Lagos spends 30 hours a week in traffic, according to one survey.

Around a third of taxis carry cargo and connect small towns to each other and to rural villages. In 2020 there were 8,784 African agglomerations with at least 10,000 people, up from 2,360 in 1980, according to Africapolis, a research project of the OECD, a group of mainly rich countries. Motorbikes make it easier to get from one to another—the average distance between two agglomerations is 20km, down from 35km four decades ago—including connections with other forms of transport.

The two-wheelers are vital for the informal economy that makes up 86% of employment in Africa. “If you were to take them away, the economies of most sub-Saharan African cities would collapse,” argues Roger Behrens of the University of Cape Town. They are a major source of jobs for young men (just 1% of drivers are female) at a time when African working-age populations are expanding faster than formal jobs. There are at least 1.5m riders in Kenya alone, more than 50% of the number of public employees.

Some effects are less welcome. Motorcycles are noisy and add to air pollution. And they crash. Africa has 3% of the world’s motorised vehicles (of all types) but accounts for nearly one-fifth of all road deaths globally, according to a report by the UN’s WHO, published last month. Motorcycles are a big part of the carnage.

Only around half of drivers wear helmets in Kampala (Uganda’s capital), Lagos (Nigeria’s commercial megalopolis) and Maputo (Mozambique’s capital); passengers are even less likely to do so. Only eight African countries have “best practice” laws on helmets, notes the WHO. And these are often patchily enforced. Rwanda, however, insists that both rider and passenger wear helmets—and actually enforces the law.

At various times some governments, such as Ghana’s, have banned motorcycle taxis. Some of the largest cities in Senegal, Nigeria and Ivory Coast have had them banned, sometimes because they are associated with crime. In other cases politicians simply think motorcycles are a nuisance and get in the way of their own cars (often large SUVs). “These bans can be very personal sometimes,” says Tom Courtright, a researcher based in Nairobi, who co-authored the FIA Foundation report.

Yet the bans tend to be evaded or withdrawn. This is partly because large groups of young men can be influential in politics, so cannot be ignored for long. Indeed, some political parties have tried to co-opt riders as ready-made youth wings. But the main reason why bans don’t work is that there is simply no good alternative for millions of Africans trying to get around.