There are a number of local authorities resposible for different aspects of the transport infrastructure in the Cambridge area.
The Cambridgeshire and Peterborough Combined Authority are the Local Transport Authority. As set out in the Transport Act 2000, local transport authorities are responsible for developing policies for the promotion and encouragement of safe, integrated, efficient, and economic transport to, from and within their area and carrying out their functions to deliver on these policies.
Cambridgeshire County Council are the Highways Authority. This is defined in the Highways Act 1980 as the body responsible for all roads ‘maintainable at public expense’ in their area that do not fall under the responsibility of the UK Government (through the strategic highways authority, National Highways). The County Council is also responsible for the creation, maintenance, and operation of the Busway.
The County Council are also the Local Traffic Authority, the body responsible for day to day management of local traffic. The key way you’ll come across this in practice is that the Local Traffic Authority are responsible for Traffic Regulation Orders (TROs) which cover things like parking, road closures, and bus lanes.
The Greater Cambridge Partnership is a city deal with central government that’s worth up to £500 million in funding to 2030, and is responsible for a number of significant transport initiatives.
The smaller (district) councils – such as Cambridge City Council and South Cambridgeshire District Council don’t have direct responsibility for transport (other than being the licensing authority for taxis) but are required to be consulted in the creation of the Local Transport Plan (LTP) by the Transport Authority. The district councils are (mostly) the Local Planning Authorities (LPAs) for their areas, although South Cambridgeshire and Cambridge City have a shared planning service – Greater Cambridge Shared Planning.
Parish councils have no formal responsibility for transport matters. As they’re much more directly connected to local residents, they’re in a very good place to be able to identify and report local issues up to the relevant higher authority.
As you can imagine, the allocation of different responsibilities to different authorities or organisations isn’t necessarily conducive to easy management, nor is it obvious to many users exactly which authority they need to deal with in the event of a problem.