High-Speed Travel in the US
Forecasts from 2025-08-23 on high speed rail and supersonic flight in the United States
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Commercial transportation depends as much on economic viability and political will as on technological limitations. High speed rail (HSR) has been available in Asia and Europe since the 1960s and 1970s, but has not yet succeeded in the United States. Efforts to build it have faced multi-decade delays and repeated cost overruns, raising doubts about if and when they will be completed. Supersonic commercial flight was available from 1976-2003, but was discontinued in the face of low demand and high operating costs. Several startups are trying to revive supersonic travel as a luxury option, but need to overcome regulatory hurdles and convince investors that their jets would be financially viable.
Seven Samotsvety forecasters discussed the timeline of possible advances in high-speed rail and supersonic flight in the United States. We made forecasts on the following questions:
When will some section of (a) the California High-Speed Rail and (b) Brightline West be open for regular commercial travel?
When will a flight that attains supersonic speeds be commercially available within the continental United States?
High-Speed Rail
1a) When will some section of the California High-Speed Rail (CAHSR) be open for regular commercial travel? (constraints: at least 100 km long, top speed ≥275 km/h)
Median forecasts:
10th percentile: 2032
50th percentile: 2038
90th percentile: Never
Background and forecast:
The CAHSR Authority was set up in 1996. Long delays and political stalemates have meant that so far, no track has been laid. As of the most recent project update, the first section — between Merced and Bakersfield — is scheduled to begin operations in 2031.
We estimate a 10% probability that some section of track opens by 2032. Our median estimate for some section of track opening is 2038. Finally, forecasters consider there to be a non-negligible (at least 10%) probability that the project never sees the light of day.
Core reasoning:
Major public infrastructure projects in the US that are funded piecemeal often fall into “development hell,” and the CAHSR appears to be one of them. Funding uncertainty raises interest rates, making them less able to borrow, further increasing funding uncertainty.
Given this reference class, the CAHSR may not necessarily be uniquely dysfunctional — the East Side Access of NYC also ran into similar levels of delays. The figure below depicts official completion projections for other such projects over time (major American public piecemeal funded infrastructure projects), normalized to the year of groundbreaking.
It’s not uncommon for projects to have initial reports predicting completion 5-10 years after groundbreaking, and then slowly get gradually delayed by years or decades. So far, CAHSR seems to be following a similar pattern. Further, in the class of high-speed rail projects around the world, if construction starts, the vast majority of them actually are completed. These may be reasons for hope.
Still, we are not optimistic. Forecasters noted that messaging by the CAHSR has consistently focused on the job-generating aspect of the megaproject, as compared to the actual infrastructure — though this may be politically necessary for buy-in. This may be related to the fact that the first segment is opening in a region that does not see particularly high travel demand. Continuing this project while the state is going through a financial crunch may become untenable at some point when the returns to the first stage are so low.
1b) When will some section of the Brightline West be open for regular commercial travel? (constraints: at least 100 km long, top speed ≥275 km/h)
Median forecasts:
10th percentile: 2028
50th percentile: 2030
90th percentile: Never
Background and forecast:
Brightline West is a private entity constructing high-speed rail between Las Vegas and Southern California. The controlling group also owns Brightline, an inter-city rail route in Florida and the United States’ only such private route.
We are more optimistic about this project, estimating a 10% chance that it will be operational by 2028. Our median forecast of completion is 2030. However, more than half of the forecasts consider there to be a 10% chance that the project is never completed, or is completed in a manner that doesn’t satisfy the above criteria.
Core reasoning:
Unlike the CAHSR, the vast majority of the Brightline West is along a freeway median, removing the scope for land disputes. Further, the Florida Brightline rail route (non-HSR), was completed on time, showing the firm’s general competence. And unlike the CAHSR, the firm has the entire funding secured for its current plan for the project.
The project is, however, heavily levered, and that may one day unravel, making the project infeasible for long enough that it becomes no longer necessary. Forecasters also noted that the target speed has been lowered once, and may be lowered further to the extent that it no longer meets the criterion of 275 km/h.
Supersonic flight
2. When will a flight that attains supersonic speeds be commercially (regularly) available within the continental United States?
Median forecasts: 10% chance by 2030, and 50% by 2043.
Background and forecast:
Commercial supersonic travel has not existed in the U.S. since Concorde’s retirement in 2003. In 2025, a Trump executive order directed the FAA to repeal the federal ban on supersonic flight over land and create a noise-based certification standard. Startups such as Boom Supersonic have raised significant funding and announced aggressive timelines, but none are close to commercial readiness. Technical hurdles around noise and efficiency remain substantial.
We forecast a 10% chance that we will see commercial supersonic flight by 2030, and 50% by 2043.
Core reasoning:
Boom appears to be the most likely full-stack startup in the space to reach the goal, and their completion target is 2028. Boom managed two successful test flights with a prototype plane in early 2025, but will have to go through regulatory approval for a new engine and airframe before they can launch commercial, and their timeline seems overly optimistic. Along with these obstacles, we are skeptical about the chance of success for any specific startup. Conditional on series B funding, startups still seem to have an under 20% rate of achieving maturity.