Heathrow currently benefits from two rings of local roads that surround the airport. They provide access to the airport, routes for through traffic and routes to and from local communities. The inner ring is formed by the airport Perimeter Road (Northern, Western, Eastern and Southern) and the outer ring by the A4, A312, A30 and A3044.
We need to respect our neighbours by reducing congestion for vehicles accessing the airport and surrounding areas. It is important that our neighbouring communities can access the airport and benefit from the improvements to local and regional connections.
Our designs must meet safety standards and will be phased to reduce disruption to users.
As a result of expansion, a section of the A4 between Colnbrook and Sipson will be removed, potentially affecting how communities to the north of the airport can access it.
To address this we have short-listed three diversion options:
- Option 2E – a new route north of the third runway between the A4 at Colnbrook and the A4 to the west of Sipson, bypassing both Harmondsworth and Sipson. This option contains a section of tunnel running under the third runway. This option re-provides east-west connectivity and creates an opportunity for new connectivity for residents and businesses, such as bus routes.
- Option 3A – this route is similar to 2E but east of the A3044 it connects to the M4 Spur, via a new junction with slip roads, to link into the A4. This option benefits from using existing infrastructure but would require the re-classification of the M4 Spur for use by local traffic.
- Option 6C – we are also considering a route south of the new runway, similar to the current A4 alignment. This route would connect the A4 east of Colnbrook to the A4 at Sipson, and would pass through the expanded airfield in a cutting or tunnel. This option has good connectivity although not as good as other options but is more complex and costly to deliver.
The A3044 connects the A30 Crooked Billet junction in the south to the A408 Cherry Lane junction near J4 of the M4 motorway.
The expansion of Heathrow will remove a major section between the villages of Harmondsworth and Stanwell Moor and connections between the A4 and A3113 routes. It will also affect access to the western side of the airport particularly from Poyle and Colnbrook.
We are proposing a replacement route to reprovide local connections. A number of options have been considered both east and west of the M25 which re-provide north-south connectivity from the A4 to the vicinity of J14 of the M25.
We have short-listed four route options for this road:
- Option 2a – a north-south route that runs under the new runway connecting to the re-aligned A4. This route would be more costly and complex to deliver and would result in the loss of some commercial and residential properties.
- Option 2ai – similar to Option 2a, but connects to a realigned A4 south of the new runway.
- Option 3d – a short, direct route east of Poyle and north of Colnbrook avoiding the village centres. This would result in the loss of some commercial and residential properties, but would help keep traffic away from existing communities.
- Option 3g – a route south of Poyle and Colnbrook, and through a gap between Colnbrook and Brands Hill. This would avoid property loss by adopting a slightly longer route but would bring traffic closer to existing communities.
Stanwell Moor Junction
This junction is located to the south west of the airport and connects the A3044, A3113 Airport Way (which provides direct access to M25 J14) and the Southern Perimeter Road.
The expansion of the airport and changes to the local road network will redistribute road traffic around Heathrow. The current access to Terminal 5 from J14a may be lost, access to Terminal 5 from the Western Perimeter Road will be lost and a potential southern access route into the Central Terminal Area (CTA) could result in more traffic on the Southern Perimeter Road (further details on the next page).
Therefore, we need to consider how the existing Stanwell Moor junction can be upgraded to deal with the expected traffic flows. We have shortlisted four options for upgrading this junction:
- Option 1 – directs through traffic on the A3113/ Southern Perimeter Road into a cutting under a ‘dumb-bell’ roundabout arrangement with potential free flow access links at ground level to access Terminal 5 to the north and Staines and Stanwell to the south. This option is less complex to build but requires more land and the loss of some commercial businesses.
- Option 2 – is similar to Option 1 but with a different roundabout arrangement. This option is operationally easier to navigate and avoids property loss but is difficult to build.
- Option 3 – maintains through traffic on the A3113 / Southern Perimeter Road at ground level and puts the roundabout below it for access to Terminal 5 to the north and Staines and Stanwell to the south. This layout avoids property loss but is difficult to build.
- Option 5* – is a two-tier free flow arrangement. This layout avoids property loss but could be difficult for users to navigate, difficult to build and requires more land.
*Option 4 was discontinued, please see the Scheme Development Report (available in Documents & Resources) for further information.
Central Terminal Area Access
The Central Terminal Area (CTA) lies between the two existing runways and is the location of both Terminals 2 and 3. The only passenger road link into the CTA is via the northern tunnel access.
We think it will be important to improve access to the CTA to ensure that passengers and others have safe and reliable journeys and that delays are minimised. The tunnel will not be affected by expansion but we are looking at measures to improve capacity through it, as well as options for a second road link to the CTA from the south of the airport.
We have two options for a southern access route:
- Option S5 – re-using the existing airside cargo tunnel for landside passenger traffic. This would require a new airside cargo tunnel to be built elsewhere at the airport.
- Option S6 – a new tunnel from the Southern Perimeter Road into the CTA.
Both options would require a new tunnel to be built but would improve access to Terminals 2 and 3, improve public transport journey times from the south of the airport and help to distribute vehicle traffic around the airport.
However they may generate extra traffic on the routes leading to and from this tunnel resulting in effects on local communities and potentially requiring further works to local junctions and more lanes on the Southern Perimeter Road. For more information on the different effects of each option please see section 8 of “Our Emerging Plans” and section 7 of our “Scheme Development Report” for more information. Both documents are available via the Documents & Resources section of this website.