Originally Posted by
Trinity 09L
Referring to the BBC plan in their link. The road in red known as the A4, disappears to the North (somewhere), this of course is an example of reducing road traffic.
Funny that you should say that.
The original NW runway plans published showed the A4 Colnbrook bypass curving south to a new roundabout just east of Poyle, from where it would continue east in a tunnel on more-or-less its original course past the northside to Hounslow and points beyond.
The revised ("optimised") NW layout, with the runway moved further southwest, doesn't leave room for the bypass. It still shows the roundabout, and the A4 east from that point under the taxiways, but the implication is that Poyle and Colnbrook are no longer bypassed but have the A4 running through them, as they had before the bypass was built in 1929.