With the reduction in regional level administration in the United Kingdom, herein “Regional" level refers to the powers of the devolved national Governments of Scotland and Wales and the Northern Ireland Executive. England is broadly swept under central-level administration or devolved to the local level through single or two-tier authorities. To be reiterated is that the UK functions on a "reserved powers" basis, according to which those matters not specified as "reserved matters" are the responsibility of the devolved governments. This means that there are generally no lists of devolved powers set in stone; consequently, the lists of devolved and local powers set out below are not exhaustive.

Transport

The Department for Transport (DfT) is a ministerial department and has overall responsibility for transport in the United Kingdom, although those aspects of transport policy that do not have an all-UK element are devolved. The UK develops policy and provides most of the funding for local transport in England, including: buses, walking, cycling and local transport (highways and rail). In other parts of the UK, this is provided by the relevant devolved administration. Westminster retains reserved powers for UK-wide transport, such as aviation and maritime policy, and strategic road and rail[1].

There are 24 agencies and public bodies supporting the DfT and powers concerning areas of road, train, maritime and aviation transport are delegated through them.

Transport services in the UK, such as rail, bus and ferry operators, are franchises that are privately owned but regulated by the state authority. These operate on varying levels of geography, whether local, regional or national. Examples include Transport for London, managing all public transport in London, and the Southeastern, GTR and Southern rail franchises that are owned by Govia, a joint venture between Go-Ahead PLC (65%) (a leading UK transport group) and Keolis (35%), a major world-wide operator of public transport[2]. The Scottish Government is responsible for the rail franchise in Scotland (ScotRail), awarded to Abellio;  the Welsh government is responsible for Transport for Wales Rail Services, awarded to Keolis Amey.

Central

UK Central Government is responsible for:

• safety and security standards in transport;  vehicle and fuel duties
• integrated transport policy
• vehicle licensing and regulation (through the Driver and Vehicle Licensing Agency and Driver and Vehicle Standards Agency)
• managing the motorway and trunk road network in England through Highways England
• the Office of Rail and Road: an independent safety and economic regulator for Britain's railways and the monitor of Highways England
• funding English local authorities as highway authorities
• setting the strategic direction for the rail industry in England and Wales – funding investment in infrastructure through Network Rail, awarding and managing rail franchises, and regulating rail fares
• setting national aviation policy, working with airlines, airports, the Civil Aviation Authority and NATS (the UK's air traffic service)
• accident investigation through the respective Air Accidents Investigation Branch, Rail Accident Investigation Branch and Marine Accident Investigation Branch. Road accidents are typically investigated at local level by police authorities and at national level by the DfT in the form of Road accident in-depth studies (RAIDs).
• the British Transport Police Authority: an executive non-departmental public body
• oversight of maritime affairs: carried out by the Maritime and Coastguard Agency.

Regional

Transport is a devolved matter throughout the UK.
The Scottish Government is responsible for:

• the Scottish road network; trunk road management; road signs and speed limits
• parking controls, bus policy, concessionary fares, cycling, taxis and minicabs
• motor vehicles and trailer description regulation
• railway services (with some exceptions); construction of new railways; railway policing; passenger rail franchise
• shipping, ports, harbours & ferries: planning and Public Service Obligation (PSO) designation
• inland waterways
• airport development planning and PSO designation; Air Passenger Duty (applying in Scotland since April 2018)
• guidance for Regional Transport Strategies (seven Regional Transport Partnerships)
• transport security.
  
  

These powers are delegated through Transport Scotland, the national transport agency.

The Transport (Scotland) Act 2019 further empowered the Scottish Government in matters of sustainable transport, including low emissions.

The Wales Act 2017 devolved the following powers to Wales:

Setting speed limits; regulations on pedestrian crossings and traffic signs; prescribing signs and approving school crossing patrol uniforms; complete powers over the bus network including to legislate on re-regulation; taxi and private hire vehicle (PHV) licensing; functions of a Minister of the Crown under legislation concerning harbours, harbour authorities and pilotage (except for reserved trust ports).

The Welsh government's responsibilities thus now cover the following areas:

• transport planning and strategy: local transport, national transport finance plans
• flying and airports: Cardiff Airport, intra-Wales air service
• roads and driving: parking permits for disabled people, road safety, road projects and highway standards
• freight: strategy and grants
• metro: South Wales Metro, North East Wales metro
• ports and harbours: harbour orders
• public transport: bus travel and bus passes
• rail: rail projects and franchises
• walking and cycling: active travel and safe routes.

Through the Department for Infrastructure (DfI), the Northern Ireland Assembly is responsible for:

• road improvement schemes
• roads policies and legislation
• active travel
• DfI roads and rivers procurement
• transport initiatives
• public transport
• waterways
• road users
• ports
• planning.
  
   

The North-South Ministerial Council, with representatives from both the UK and the Republic of Ireland, meet in the Transport Sector to make decisions on common policies and approaches in areas such as co-operation on strategic transport planning, including road and rail infrastructure and public transport services and road and rail safety.

Local

English county councils are responsible for:

• producing local transport plans
• drafting the general transport strategy
• passenger transport and highways. 

English district councils are responsible for:

• parking and other revenue collection from transport
• local planning decisions that invariably involve transport issues. 

English unitary councils are responsible for:

• producing local transport plans
• drafting the general transport strategy
• passenger transport and highways
• parking and other revenue collection from transport.

In Scotland, Regional Transport Partnerships (RTPs) manage local and regional transport policies. These are steered by boards consisting of councillors from each of the constituent local authorities.

Local authorities in Wales cover: highways construction and maintenance, maintenance of bridges and structures, road safety, public transport, active travel, community transport, transport planning, traffic management, congestion management and utilities work coordination.

Local authorities in Northern Ireland are responsible for off-street parking.

Responsible ministries/bodies

UK Department for Transport

Devolved governments of the United Kingdom

Department of Transport, Wales

Transport Scotland

Northern Ireland Department for Infrastructure

Local councils in each part of the UK

Sources

UK Department for Transport: https://www.gov.uk/government/organisations/department-for-transport

Scottish Government, Transport policy: https://www.gov.scot/policies/transport-policy/

Transport (Scotland) Act 2019: http://www.legislation.gov.uk/asp/2019/17/enacted

Transport Scotland: https://www.transport.gov.scot/

Concordat between the Department for Transport and the Scottish Executive, 2nd edition, 2007: http://www.scotland.gov.uk/Resource/Doc/172612/0048201.pdf

Department of Transport, Wales: https://gov.wales/transport

Northern Ireland Department for Infrastructure: https://www.infrastructure-ni.gov.uk/

Louise Butcher, Fintan Codd and Rachael Harker, Transport policy in 2010: a rough guide, House of Commons Research Paper 10/18, 19 March 2010.

Scotland Act 2016 - Sections 40-46 and 55-57 and Schedule 2 relating to transport matters: https://www.legislation.gov.uk/ukpga/2016/11/contents/enacted

Wales Act 2017 – Sections 26-38: http://www.legislation.gov.uk/ukpga/2017/4/contents/enacted

Local Government Association (LGA) (England): https://www.local.gov.uk/

Convention of Scottish Local Authorities (COSLA): https://www.cosla.gov.uk/

Northern Ireland Executive: https://www.northernireland.gov.uk/

Welsh Local Government Association: https://www.wlga.wales/home

[1] https://researchbriefings.files.parliament.uk/documents/SN03156/SN03156.pdf.

[2] https://www.govia.info.