Based on my email exchange which I have largely copied below, consultation was done by Andrew Cassidy of Tfl surface transport department in June 2015. Letter with diagrams through the door I think.
Some of my comments were...
The bollards on the central island are regularly damaged/wiped out by larger vehicles turning into Devonshire Road. A yellow hatched junction box on Waldram Crescent for vehicles turning into Devonshire Road would be a most welcome addition and improve visibility for turning traffic as well as avoiding gridlock.
...the statement in your letter that 'the footway widening will have no impact on vehicles' is perhaps a little naive. The widening work looks likely to reduce the capacity for two 'waiting' cars at the final point of the junction down to one. Therefore unless there is then going to be a left turn only instruction, any vehicle exiting Devonshire Road and turning right will halt the flow of traffic there until they are able to make their manoeuvre.
During normal/busy traffic periods, a poorly positioned car turning right at that junction can cause that wait to be lengthy and create a backlog of traffic extending some way up Devonshire Road, which is already a rat run.
Your proposals appear to make that a permanent state of affairs and I would be interested to see an impact study done by temporarily creating the proposed scenario for a few hours before it is made permanent.
And his reply was...
Thank you for your comments on our proposal to make some changes at the Devonshire Road/Waldram Crescent junction. I have met with the Project Manager, Robert Hunter, who has reviewed the plans against your comments.
We are confident the minor change to the footways and the restoration of a pedestrian refuge island will have limited impact on the width of the roadway at the point where vehicles enter and exit Devonshire Road. As such, our view remains they will not make it more difficult for vehicles to exit and enter the road at the same time.
As a matter of course, junction changes are reviewed to ensure sufficient space remains for larger vehicles, like vans and garbage trucks, to pass through it, not just motor vehicles.
There are strict design rules for the use of yellow-hatching at junctions and it would not be an appropriate treatment for the Devonshire Road/Waldram Crescent junction. However, we will look at installing ‘Keep Clear’ road markings.
The Project Manager considered your suggestion to use some form of temporary arrangement to ‘model’ the changes and gauge the impact on traffic. His concern is that setting out cones to mark the new kerb line will change driver behaviour excessively. Cones indicate works or hazards and drivers will usually respond by becoming more cautious. As a result, the way they approach the junction and make their turns would not be same as if they were confronted by a physical change.
I’d like to reiterate that the plans for the junction were reviewed and there is no indication the walkway changes will unduly impact on the width of roadway available for vehicles entering and leaving Devonshire Road.
Please do not hesitate to contact me if you have any further concerns or questions.