Heathrow Airport has launched a public consultation on its expansion plans, revealing that it hopes to realign the M25 and run it into a 7 metre deep tunnel under the third runway.
The consultation document states: 'Our current thinking is to re-position the M25 carriageway approximately 150 metres to the west, lower it by approximately 7 metres into a tunnel and raise the runway height by 3 to 5 metres so that it passes over the M25 between J14a and J15.
Image Heathrow
'The motorway will then re-join its current route. Crossing a motorway with a runway or taxiway has been done successfully at other airports around the world such as Paris (Charles de Gaulle) and Atlanta.'
Heathrow is clear that the M25 'has to remain open during the construction of the proposed north west runway'.
It adds: 'We are also considering whether there would be benefits in introducing collector-distributor roads alongside the M25 that improve journey times for both airport and non-airport traffic. Such roads are however complex to build, require more land and are more costly.'
There are also plans to re-position parts of the A4 and A3044 and improve local access roads and junctions.
Key infrastructure proposals:
- Cutting expansion costs by £2.5bn
- Three shortlisted options for the new north-west runway with length varying from between 3,200 and 3,500 metres
- Potential locations to expand terminal infrastructure: east of Terminal 2, west of Terminal 5 or a new satellite terminal by the new runway
- Proposed alignment of the M25
- Options for changes to local roads and possible changes to two junctions leading to the M25
The consultation comes ahead of a Parliamentary vote in the first half of 2018 on a National Policy Statement for a new north-west runway at Heathrow, which will set out the policy framework for Heathrow’s final planning submission.
Heathrow suggested the 10-week consultation is set airport to be one of the largest public consultations in the country’s history.
Alongside the physical changes needed to build a new north-west runway and operate an expanded airport, there are also principles of new airspace design and plans to manage the effects of expansion on local communities and the environment.
Heathrow said: 'The second part of the consultation relates to potential principles, or ‘rules’, that could apply when designing the new airspace required for an expanded airport. Airspace across the country is being modernised as it has changed little since the 1960s. Changes to airspace will ultimately improve resilience and punctuality for passengers while reducing noise, emissions and the number of late-running flights for local communities.
'At this early stage, future flight path options are not being consulted on.'
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