Billionaire tech entrepreneur Elon Musk on Monday announced he would publish the design for a new mode of transportation in mid-August.

The man behind Tesla Motors, Solar City and SpaceX has frequently mentioned the "Hyperloop" -- which he hopes will replace trains -- but has offered little to no details. Musk has said the Hyperloop was inspired by California's proposed high-speed train system, which he described as the slowest but most expensive bullet train in the world.

"Even if I'm sort of wrong about the economic assumptions behind the Hyperloop, it would still be a really fun ride," Musk said at the D11 Conference earlier this year. "It's a cross between a Concorde, a railgun and an air hockey table."

He told Pando Daily the Hyperloop would be twice as fast as a commercial jet. People could travel from San Francisco to Los Angeles, more than 300 miles, in less than 30 minutes. It would cost less than high-speed rail "because the fundamental energy cost is so much lower," Musk explained.

Like the technology developed for SpaceX, the Hyperloop design will not be patented, Musk said on Twitter. Though patents might protect his tech from being stolen by other companies, his main competitors are governments.

"If we published patents, it would be farcical, because the Chinese would just use them as a recipe book," he told Wired last year.

Instead, the Hyperloop design will published open source, allowing anyone to view or reproduce them.

Watch video, uploaded to YouTube in March, below:

["Futuristic Interior" on Shutterstock]