The idea of underground tunnels, to expand space for cars, at an enormous cost of £190m, is an expensive, outdated solution. Cities across northern Europe have shown that the way to deal with congestion and city growth is by creating extremely high-quality facilities for cycling, not filling it up with cars.
High-speed, smooth cycleways, completely separate from pedestrians and cars, which enable large numbers of people to travel in a compact city, would do far more than expanding space for cars, and could be achieved far more cheaply.
Although many people cycle in Cambridge, the fact that so many people still do not choose to cycle shows that current conditions need to improved. Instead, shared-use pavements, barely more than a blue sign on a pavement, are still commonly seen around the city. Likewise, getting decision-makers to remove even a single obstructive car parking space in favour of cycle parking or a cycleway is next-to-impossible.
With tens of thousands of new houses in the area, we need to be seeing cycling rates doubling from 20-25% to 40-50% within a decade or two. New residents should be able to move into a city where they find cycling as the obvious and easy option.
All that is really missing is political will at a local and national level to see cycling invested in, so that people aren't forced to sit in traffic jams because they're too scared to cycle.