With resources like energy, land, water and raw materials under strain, there is a growing awareness of the need for alternative forms of transport that generate less pollution, consume fewer resources and help cut greenhouse gas emissions.
Kuna sellised ressursid nagu energia, maa, vesi ja tooraine on kahanemas, hakatakse üha paremini mõistma, et vajatakse alternatiivseid transpordiliike, mis tekitavad vähem saastet, kulutavad vähem ressursse ja aitavad piirata kasvuhoonegaaside heitkoguseid.