On the 10th July, the National Infrastructure Commission published the National Impact Assessment (NIA). The NIA makes recommendations for how the infrastructure needs and priorities of the country should be addressed. Along with my colleage Andrew Smith, I developed a baseline projection for population and employment in UK cities and undertook sensitivity testing of projections to consider outcomes under different assumptions about future growth patterns. They then developed alternative scenarios for population and employment growth in cities reflecting transport infrastructure constraints and housing constraints. The headline conclusion reported in the National Infrastructure Assessment is that transport networks are close to capacity in many UK cities.
The full Assessment can be found here while my report can be found in the supporting documentation here.