Route
Junction number
4
Markerpost
25.0 km
Name
Airport Interchange
Terminus
Not a terminus
Other routes
A408
Authority
Restricted turns
Full access
Services
No services
M4 J4 Airport Interchange
Layout and signage
|
Uxbridge Heathrow  T2 & 3A408 |
(A408) | 
|
(A4) |
Heathrow T2 & 3 Uxbridge A408 |
Lane configuration
- Lane 1 exits and does not return.
- Lane 2 continues ahead.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
- Lane 5 continues ahead.
- Lane 1 is gained from the entry sliproad.
- Lane 2 continues, with option to exit.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
- Lane 5 continues ahead.
Other events
Variable Speed Limits apply
- Variable Speed Limits apply
What's new
The sunlit uplands
On Saturday 31 May something historic happened. The Heads of the Valleys Road was finally complete.
Grand openings
Our much-loved Opening Booklets section has two new publications for you to explore, and we’re making some overdue changes to make them easier to find and easier to read.
Silver bullet
The Silvertown Tunnel is finally open for business. One question remains: what’s it for?
Have you seen...
Alley by gaslight
Some of Central London's quieter streets are still, surprisingly, lit by old and rather beautiful gas lanterns. Here are a few, by day and by night.
About this page
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