An important way to reduce the greenhouse gas emissions that transport produces is to encourage and enable people to travel less. People travel less overall when they switch from private vehicles to public transport, walking or cycling, for reasons that will be explained. They travel less if their work is closer; if shops, health services and education are closer; and if family, friends and leisure activities are as well. They travel less if several purposes of travel can be covered in one trip, which is more likely if the places they need to visit are closer.