Elon Musk published his preliminary plans for the Hyperloop yesterday, and it quickly became clear that there are some kinks that need to be ironed out.

In his report, Musk noted a few areas where the project needs more work, including station designs and the control mechanism for Hyperloop capsules.

Then there's the question of why there's no space for a bathroom on this thing, an inconvenience that would likely violate regulations.

But there's a more fundamental issue Musk's Hyperloop would have to overcome: right of way.

As Musk says, the elevated Hyperloop would require less land than a railroad, so getting the rights should be easier than for the current high-speed rail project.

But his argument that by building it on pylons along Interstate 5, "you can almost entirely avoid the need to buy land," is less solid. The plan is to construct the tube in the highway's median.

It sounds like "an elegant solution," Robert Puentes, a senior fellow with the Brookings Institution's Metropolitan Policy Program, said in an interview. The problem is, that land is not necessarily free, vacant, available space. The government owns it.

If California wanted to build something there, it wouldn't be too tricky. Getting building rights for a private venture would be "much more difficult," Puentes, said, and for a public-private project, it would be "harder, but not impossible."

Attaining right of way would get even more difficult in the denser areas near San Francisco and Los Angeles.  There, the median land might be reserved for projects like more roadways.

Puentes said he is impressed with the scale in ingenuity of Musk's proposal, and that big projects like this are important.

And even if the Hyperloop is not built the way Musk's report lays out, a prototype or even studies for a prototype could lead to new innovations. It "may turn out to be a transformational type investment," he said, even if it never takes people from San Francisco to LA for $20.