Sustrans is a United Kingdom-based walking, wheeling and cycling charity, and the custodian of the National Cycle Network. Its flagship project is the National Cycle Network, which has created 12,763 miles (20,540 kilometres) of signed cycle routes throughout the United Kingdom including 5,273 mi (8,486 km) of traffic-free paths. The rest of the network is on previously existing and mostly minor roads, in which motor traffic will be encountered.