Should HS2 carry adjacent cycle track?

I think I've posted about this before, but I simply don't think 'more transport capacity' is the answer, whether that's road or rail. It's a pious hope that people will drive less if you increase railway capacity, but that only applies to people who already want to travel by train in preference to driving. Sure, there are some, but if you build more rail capacity on top of the existing (and constantly-increasing) road capacity, you cause more travel, full stop. All I've seen suggests that driving then doesn't go down but rather increases, for the simple reason that processes that increase the need to travel, by whatever mode, then accelerate even more. The thinking that it's OK to have functions far apart that should be close together becomes more normal, because we have great transport links, right?

People sometimes think we must already have hit 'peak travel', but we definitely haven't; that would only be if everybody didn't live anywhere permanently, which is never going to happen. There is immense potential still for the need to travel to increase that we haven't tapped yet.

Transport policy is essentially driven by the idea that in order to grow the economy, we must create more movement, so that more connections can be made more easily. This means more transport capacity. However, this also ends up changing the economic landscape, and in turn people's travel behaviour, which becomes less efficient (when they make bad choices), or is forced to become less efficient (e.g. when they can no longer do what they would choose to do).

The economic landscape can be changed by fewer big players capturing larger markets, e.g. you build a dual carriageway out of town to the out-of-town hypermarket and the shops in the traditional, well-connected centre suffer, because a single competitor now only needs one site, instead of many smaller city-centre ones, to attract large numbers of customers who fill their car boot there. Transport choices are affected because where people might have walked or cycled, they now drive.

Railways are obviously not as bad as motorway-building, but initially they did much the same things that motorways have been intensifying. If you build railways, whether suburban commuter railways or major railways connecting cities that don't stop in the smaller places, there likewise tends to be concentration of activity, which in itself isn't a bad thing, but which if driven to excess is not desirable. I happen to think that we've long exceeded a desirable balance between over-concentration and even distribution in land development, and that we must reduce transport capacity, alongside a better organisation of the economy. I would support removing motorways and replacing them with railways on the same alignments, alongside lower-capacity roads, returning dual carriageways to lower-capacity roads, and so on, while doing the necessary work on re-planning land use to reduce the need to travel first and foremost.

I doubt that explains it well enough, but in a nutshell--reduce capacity, reduce the need to travel, and rebalance the economy to benefit smaller, more local players.