If more people used them trains and buses would be able to run much larger networks thus making the 20 mile commute via train reasonable. However until people use them the network cannot be that large.
If the transit network was that large the freeway network in cities would not be worth it, thus further biasing trips to the train. However there is no easy way to get there from here.
Build it and they will come - you can't expect everyone to get out of their cars and start using public transport, then somehow use the slight increase in ridership revenue to sponsor huge infrastructure projects. Simply put: the government needs to throw down SERIOUS capital and political will to build out 20 miles of trains all around a metropolitan area.
We need to get away from the myth of single people and their small steps changing the world...we need our governments to actually invest in their own society's well-being and structure.
Right now transit construction costs are out of control in the US. (Road is only slightly better). Spain is able to build subways for about 1/5th the cost of New York city. Nobody knows why - we can find people doing nothing, high wages, and more harder rock, but all these together are just a fraction of the cost difference. Until this problem is solved we are better off building roads because we can afford them.
Thus if you want to advocate for build more, you should first advocate for figuring out how to build cheaper. (whatever this means - though if you sacrifice safety I'll oppose you)
A substantial part of the problem in the US regarding transit projects is also lack of practice and atrophy of experience and capability.
In the past 50 years, we didn't build those sorts of projects frequently. When we did, they were often one off projects in one city not repeated until another 10 or 20 years passed, and there have rarely been these sorts of projects going on in many places around the country at once.
As such, you've got:
- A very small number of suppliers for anything, especially with any track record of succeeding at contracts in North America, because the market has been unable to sustain more. Competitive bidding isn't when you get 3 bids and only 1 or maybe 2 of them fully meet your needs/requirements.
- Very few people with any real depth of expertise on building these projects on your management side, so running them effectively is unlikely at best. International hires may have more experience building a subway in the abstract, but that doesn't help them navigate very different regulatory/permitting/planning/contracting environments.
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I'm not necessarily saying "just throw money at it and eventually they'll figure out how to do it better", but to some extent we're never going to get to faster/cheaper construction until we're actually doing it consistently.
If the transit network was that large the freeway network in cities would not be worth it, thus further biasing trips to the train. However there is no easy way to get there from here.