About 70% of all travels in Africa are done by foot. The impact radius of a person is 5 km which equals to 1,5 hours walking. Often education sites, healthcare units or markets are further away and therefore nearly impossible to reach on a regular base.
With a bicycle the impact radius of an individual is 4 times bigger and one can carry up to 5 times more than walking. This means schools, markets, healthcare units and many other things are "suddenly" within reach.