Lusaka, Zambia (CNN) -- In rural Zambia, a bicycle is one of the most important possessions someone can have.

At one school, when they were given out to pupils by World Bicycle Relief, the roll increased from 300 to 867 pupils.

Headteacher Michael Gogolola explained: "Bicycles in Africa, especially in this part of Zambia, they are more valuable than a vehicle, because they use them even for grinding mill, they use them for transport to the hospital, to the clinic and to the school.

"When we came to this school, the enrolment was 300, now when the World Bicycle Relief came with bicycles, even the girls who had left school, just because they heard about the bicycles, they came back to school."

Not all the 867 pupils have bicycles, but those who do treasure them as a lifeline in an impoverished country and a powerful incentive to stay in school.

World Bicycle Relief is a Chicago-based organization which began by providing bicycles in Sri Lanka after the 2004 tsunami.

In 2006 it moved on to Zambia, where it began distributing bicycles to healthcare workers helping people living with HIV and AIDS, and in 2009 started giving them to schoolchildren as part of its Bicycles for Education Empowerment Program.

World Bicycle Relief has so far supplied 30,000 bicycles in Zambia, as well as training a network of maintenance mechanics.

Dave Neiswander, World Bicycle Relief's head of Africa operations, said: "It's connecting people with education, it's connecting people with healthcare, it's connecting people with their own economic development. It's a tool to help themselves."

The bikes themselves had to be designed to cope with the rough ground and heavy loads that many people need to carry.

"Our bicycle is designing to withstand the difficult terrain of Africa," said Neiswander. "The rack can withstand 100 kg, that's ideal if you're taking produce to market or someone to clinic. We use heavy duty rims and spokes, reinforce the tires, it's basically a tank."

World Bicycle Relief administers its program in partnership with the Zambian Ministry of Education, community organizations and several other international NGOs.

The organization points out that many children in rural Zambia do not complete their education because their families -- especially families with HIV or AIDS -- are dependent on their children's economic activity.

Because many children travel long distances to school, it identified providing safe, reliable transport as a key way of keeping children in education longer.

Zambia has the world's third highest death rate and second shortest life expectancy of 38, according to the CIA World Factbook.

The county is estimated to have 1.1 million people -- 15 per cent of the adult population -- living with HIV or AIDS, which kills an estimated 56,000 people a year. It also has the world's eighth highest infant mortality rate of more than 10 percent.

Among those who have received one of World Bicycle Relief's distinctive black bicycles is 15-year-old Fewstar Walweendo. She uses it to cycle the two kilometers to Gogolola's school after completing her daily chores, including sweeping the yard, making breakfast and cleaning the plates.

Her deputy headteacher Monica Mtongadaka said: "To a Zambian child, to a rural child, to have a bicycle really motivates, because it eases her movement to and from school, and that's what's happened to Fewstar."