I think when looking at road systems it can be hard to create something that is great for maximising vehicular traffic flow and keeps cyclists safe. Roundabouts fall into the keeping traffic flowing while making cycling unsafe category.
Bring in spatial constraints and you can end up with something horrible that is extremely hostile to people wanting to cycle.
As an exercise in rethinking Churchill Bridge Roundabout I began looking at turbo roundabouts. Something highways engineers use to create a high volume vehicular throughput.
A specific form of roundabout for motorists, with a spiral pattern that commits motorists to choosing the correct lane before entering the roundabout. Lane changes on the roundabout itself are eliminated
And I came up with this:
The Churchhill Bridge Turbo Roundabout Proposal (3) pdf is probably clearer.
I’m really uncomfortable with creating a Wellsway cycle lane to the right which ‘forces’ somebody cycling to take a primary position to then access the new cycle crossings. So for people that are uncomfortable with roundabouts, it’s a big ask to get them to do this just to access a traffic free way to negotiate the roundabout.
I did try and have a west crossing point, but the sight lines make it phenomenally dangerous and even the east crossing point is probably inadvisable.
For people comfortable with cycling, the roundabout now offers a lot more ‘control’ as taking the lane controls the traffic around you. No longer will you be under/over taken
Comments welcome. I have submitted it to Highways for consideration, particularly as the layout fixes the accident blackspot which is the Wellsway leg of the current roundabout.