Airplanes and pilots will also be a dime a dozen I suppose, but perhaps it will even put.
Rail is best used for freight.
Autonomous busses and cars (electric) are the best long-term solution for travel.
The best approach is simply to enact a Carbon Tax and let the market figure it out.
We would be better off promoting mass-contraception to the developing world and halting land clearance in terms of massive targeted CO2 reductions.
You don't even necessarily need special high speed rail, just more rail makes it more high speed because you can mix slow and fast traffic (e.g. no-stop direct trains can run side by side with freight and services that makes 10 stops).
Speed doesn't have to come up so much to at least beat road traffic.
"...let the market figure it out" would work in a market that isn't already so strongly shaped by subsidies, regulations, and nationalist protectionism.
Autonomous vehicles will have a very large and currently underestimated impact on all kinds of other modes of transportation, but there is a wide range of expert views on when that will happen.
I think high speed rail could be potentially a game changer for the job market. In the UK if you could easily commute in from Birmingham or Newcastle then London salaries would be more accessible outside London.
The other interesting angle is what will happen to electricity emissions as demand drops, it should increase the market share of renewables as the highest cost generators drop out first.
Also, my hope is that low oil prices drive US frackers out of business (US shale needs ~$40-90/barrel to break even, current WTI price as of this comment is a bit below $30/barrel); this will cause the price of natural gas to spike, causing utility scale battery storage combined with renewables to become immediately cost effective against quite a bit of current natural gas fired generation. Battery storage is already replacing the most expensive "once through" peaking plants (these are essentially jet engines bolted to the ground), and as the economics become more marginal for more efficient combined cycle gas turbine (CCGT), battery uptake will increase. That firm capacity is permanently clean moving forward.
These are "one way ratchets" we need to find every opportunity to pull. I will concede that low oil prices do not help with efforts to electrify transportation; the fight continues for a carbon tax and outlawing combustion whenever possible.
https://en.wikipedia.org/wiki/Phase-out_of_fossil_fuel_vehic... (Jurisdictions with planned fossil-fuel vehicle bans)
https://www.lazard.com/perspective/lcoe2019 (Levelized Cost of Energy and Levelized Cost of Storage 2019)
https://spectrum.ieee.org/energywise/energy/renewables/what-... (How Inexpensive Must Energy Storage Be for Utilities to Switch to 100 Percent Renewables?)
https://www.theguardian.com/environment/2020/mar/12/wind-and... (Wind and solar plants will soon be cheaper than coal in all big markets around world, analysis finds)
https://pvbuzz.com/renewables-capacity-overwhelms-coal-gas-o... (United States: Over the next three years, renewables will add nearly 50,000-MW of new capacity and be more than a quarter of total, while gas, coal, oil, and nuclear will drop by 4,200-MW)
I dont understand this if the $30 price is driven by the saudis and russians. There was immediate talk of furloughs/layoffs and striking rigs. The rigs (and crews) can go up and down in a matter of weeks. The wells and equipment will persist and be mothballed, or acquired in a fire sale. Why wouldnt production start up as soon as the price goes back to $60?
I argue this is going to go on for more than a few weeks. Saudi Arabia and Russia can hold out longer than most over leveraged US fracking orgs, especially with the US credit markets in turmoil. No one is going to be racing to extend further credit to frackers already in financial distress. Production won't start back up immediately because it'll take time to start back up.
If you drive US frackers out of business, you'll also spike oil prices. Fracking has added so much supply to the world that it's turned the US into an oil exporter on occasion[0]. Removing that much supply from the markets would cause it to tighten, and by doing so would make fracking viable again.
[0] https://www.cnn.com/2019/03/08/business/us-oil-exports-saudi...