Last week, the independent California High-Speed Rail Peer Review Group recommended that the state legislature not proceed with funding the proposed Los Angeles–San Francisco project. Its argument was grounded in concerns about “the California High-Speed Rail Authority’s plan to start construction without any assurance of future funding from the federal government,” according to The Wall Street Journal.

The California High-Speed Rail Authority responded with a “you’ll be sorry” statement, asserting that it will cost Californians more not to build the system. It argued that the cost of expanding airports and highways will total $171 billion, a sum much greater than the rail system’s projected cost of $98 billion to $118 billion. This claim is questionable at best.

It also illuminates the methodological trickery woven into the rail supporters’ argument.

As Wendell Cox and Joseph Vranich write in today’s Wall Street Journal,

Proponents based their estimate on train capacity (including empty seats) of 1,000. Their rail plan calls for trains with only 500 seats, but this fictional doubling of capacity nicely boosts the amount of highway construction they can claim would be needed if the train line isn’t built. The authority also assumed that more than twice as many trains would run as they now plan to run when the line is complete. They even include the cost of some highway expansions that would not be needed for hundreds of years at normal growth rates.

The bad assumptions do not end there. In their assessment, authority planners count on hyperbolic ridership levels. Their projections for new demand for high-speed rail travel are inflated, which allows them to claim that highways throughout the Los Angeles–San Francisco corridor would have to be expanded by three lanes—regardless of current demand and congestion levels.

The fabrication of facts has squelched the hype surrounding other high-speed rail projects. Wisconsin Governor Scott Walker (R) and Ohio Governor John Kasich (R) ended high-speed rail projects when it became known that the trains wouldn’t exactly run at high speed. Cox described the demise of the proposed Tampa-to-Orlando rail line last year: Florida Governor Rick Scott (R) decided against funding this project, which would have put taxpayers on the hook for $3 billion in cost overruns plus operating subsidies.

High-speed rail remains one of the most costly forms of transportation. Heritage’s Ronald Utt has enumerated the fiscal pitfalls, pointing to lower-than-expected ridership rates, rising ticket prices, and exorbitant government subsidies in other countries with high-speed rail systems. As is the case in California, the price tag for high-speed rail projects often exceeds original estimates and puts an additional burden on states and taxpayers already struggling in a weakened economy amid massive budget deficits. How irresponsible and misleading it is, then, of the authority to keep pushing for the California project, especially when the methodology supposedly bolstering its argument is anything but sound.