my impression was they were claiming they could fund it by developing the land freed up by knocking down the flyover. is that wrong?
That's the theory. Putting the A4 underground would release a strip of land that could be 2-3 miles long and presumably developers would be queuing up to build on it.
There doesn't appear to be a proper study on the economics and feasibility yet, however. Surface roads would still be needed for access to all those new developments and anything involving tunnel boring machines will mean big construction sites at the ends.
That's the theory. Putting the A4 underground would release a strip of land that could be 2-3 miles long and presumably developers would be queuing up to build on it.
There doesn't appear to be a proper study on the economics and feasibility yet, however. Surface roads would still be needed for access to all those new developments and anything involving tunnel boring machines will mean big construction sites at the ends.