This is a BRT line running for about 20km between Cambridge and St. Ives. It is unique (or very rare) as the bus drives along a special track without needing to steer and car traps prevent cars from accessing the busway. On top of this, there is an active travel corridor that runs along the entirety of the busway. It is one of the longest paved traffic free routes in the UK and is a cool example of how public transport and active travel can be co-developed.