At the heart of the infrastructure strategy for this Autumn Statement is a £15bn spending plan for the strategic road network, which has proven controversial with local transport experts, together with £5.8bn for local road maintenance, £2.3bn flood defence investment and a new cash boost for cycling.

The £15bn confirmed this week – previously outlined in the 2013 Spending Review - for the core network of motorways and main A-roads is legislated for under the Infrastructure Bill and will become the inaugural investment strategy of that act, which also converts the Highways Agency into a Government owned company.

Under the strategy the Government seeks to pump cash into reforming the strategic road network to provide smarter, safer and less congested roads. The schemes would build a core network of Smart Motorways centred on connections between the key cities such as Manchester, Leeds, Birmingham, Bristol and London.

The Department for Transport (DfT) aims to convert this entire core motorway network Smart Motorways within a decade - converting the hard shoulder into an extra running lane and providing improvements in traffic flow technology.

The Department also will push the funding into upgrading key A-roads such as the A1 and the A303 into ‘Expressways’ dualling these major routes and bringing them up to the same quality and safety as motorways.

However experts at the Local Government Technical Advisers Group (TAG) told Transport Network: ‘There is a substantial weight of evidence to show that enlargement of such roads increases traffic substantially within a relatively few years of the opening of such roads or road improvements.

‘TAG believe that a large number of the Highways Agency projects will, after a fairly short time, increase congestion on the overall journey and local roads particularly in urban areas.’

DfT officials conceded that the investment was specifically for the trunk road network but highlighted that extra investment was being put into the local roads network through other funding sources most notably the £5.8bn being put into capital maintenance funding from 2015 to 20120/21, which ahd also been outlined in 2013.

The National Infrastructure Plan 2014 published in tandem with the Autumn Statement has confirmed regional roads cash allocations for the next parliament together with controversial reforms to this local capital maintenance funding. Further details can be found here.

Chancellor of the Exchequer, George Osborne, said: ‘Our plans will transform some of the country’s most important strategic routes, with ambitious projects to dual the A303, A1, A27 and the A47 as well as spending on important local infrastructure boosting productivity and helping local economies.

‘For years our roads have been neglected. Now that this government is fixing the economy, we can afford to invest properly in our roads – unlocking jobs for the future and local growth by creating a road network that is fit for the 21st century.’

However Michael Dugher MP, Labour’s shadow transport secretary was scathing of the announcement: ‘This is just yet another re-announcement on promised road improvements. The Government has 'announced' plans for road investment at least three times since 2013. And no additional money has been announced.’

Cllr Peter Box, transport spokesman at the Local Government Association, said: ‘It is (also) time to stop treating our strategic road network in isolation. Increasing motorway lanes and improving A-roads alone won’t ease congestion but will only speed up cars between growing delays and traffic jams on local roads.

‘It would now take councils more than a decade and £12bn to bring our roads up to scratch. That is why we are calling for the Government to inject a further £1bn a year into local roads maintenance by investing just two pence per litre of existing fuel duty. Our recent national polling found 83% of the public back the plan.’

The Chartered Institution of Highways & Transportation (CIHT) said the roads plans needed to be part of a national transport strategy, as ‘roads should not be looked at in isolation’.

It added there needed to be consideration of the whole life revenue costs of maintaining road assets as well.

Chancellor Osborne also reiterated plans for major flood defence schemes over the next parliament with 1,400 projects chosen to receive government investment in moves expected to improve protection for 300,000 homes.

The schemes chosen to share the £2.3bn planned for the next six years are expected to help prevent over £30bn of economic damage to England.

Major investments are earmarked for areas such as the Thames Estuary, where £196m will be spent, and for the Humber Estuary where £180m improvement programme is planned.

Flood defences in Somerset are due to receive £15.5m in additional funding over the next six years, which is forecast to protect 7,000 local properties. The Somerset Levels and Moors are due to see £4.2m of flood defence improvement works after the region was badly affected in last winter’s storms.

Labour’s shadow environment secretary, Maria Eagle, said the country was ‘playing catch up on flood defences’ following cuts to the flood protection budget of over a £100m a year made in 2010.

‘There have been reports of a £500m black hole in these plans which the Government expect communities to meet themselves. This kind of uncertainty is unfair on those affected - we need a proper long term plan for infrastructure investment including flooding which is why we have called for an Independent National Infrastructure Commission,’ Ms Eagle said.

The Government also announced an extra £214m investment in cycling to improve infrastructure on the strategic road network and extend its Cycling Ambition Cities programme. The cash is split into two pots with £100m coming from Highways Agency funding under the Government’s Roads Investment Strategy.

This cash investment will be invested over six years to help safety and accessibility issues for cyclists and walkers travelling alongside and crossing Britain’s strategic road network.

A further £114m is planned to support the Cycling Ambition Cities Programme for the next three years on top of the £77m announced two years ago for the scheme.