With his Hyperloop proposal, Elon Musk isn't the only entrepreneur proposing ways to rev up American transportation.
The man who brought us sleek, clean electric Tesla cars and SpaceX -- a private space program that successfully sent a payload to the orbiting space station -- is setting his sights on a radically different mass transit proposal called Hyperloop.
Giant vacuum tubes would suck travelers across thousands of miles in a matter of minutes.
Technology in the Digital Age is spurring creative ideas aimed at improving -- and even reinventing -- the way humans travel. The issue is becoming a pressing one with increasing traffic and vehicle emissions.
Musk's idea is one of countless transportation concepts being bandied about -- some of which may blow your hair back, others that may amount to pie in the sky. Some may be closer to reality than you think -- like driverless cars and space tourism. For other ideas, the future is murky.
You be the judge.
The media loves a good gee-whiz story. Remember the Segway? When that was announced in 2001, we read that these two-wheeled transportation machines would change the way we commute and how cities would be designed. How many Segway owners do you know? Or how about the Shweeb, a pedal-powered transportation system that so impressed the folks at Google, the company gave its inventors $1 million for research and development. In the three years since Shweeb won the award, it hasn't made a lot of news. The lesson is, it's a long way between the drawing board and reality.
Let's take a look at some of the ideas floating out there that may influence the way we travel from Point A to Point B in the future.
By 2019, a small aircraft-maker reportedly plans to start offering a $5 million two-seater jet aimed at business execs who want to fly as fast as 720 mph -- close to the speed of sound. But, mostly, the buzz around the future of flight surrounds something even faster: supersonic combustion ramjets -- aka scramjets.
Imagine flying from New York to Tokyo in under two hours.
Scramjet technology could make that dream a reality. Experts predict scramjet engines could propel aircraft as fast as 15 times the speed of sound, according to NASA. Unlike conventional jet engines, scramjet engines have virtually no moving parts. And unlike rockets, scramjet engines would burn oxygen from the atmosphere instead of having to carry heavy tanks full of oxygen.
The result: a more efficient vehicle for military or commercial purposes.
Last year the Pentagon tested a 25-foot long scramjet called an X-51A Waverider. Such technology could be used to develop "cruise missile-like weapons that could reach a target on the other side of the planet in minutes instead of hours," one expert told CNN. Another application for the technology, he said, is an "aircraft which could put a quick-reaction force on a far-off battleground within hours instead of days."
A UK-based outfit called Reaction Engines has been working on scramjet technology. It produced a video to show its vision for a passenger aircraft called the A2, which would fly five times the speed of sound.
This month Reaction Engines announced a partnership with the European Space Agency to figure out its next system to launch vehicles into orbit.
Since 2008, the Obama administration has been pushing the idea of high-speed rail, by offering federal money to interested states.
One of those states is California.
On its website, California's high-speed rail project still officially promises service from San Francisco to the Los Angeles area in under three hours at more than 200 mph.
But the program's initial projected cost of $34 billion has ballooned to $118 billion. Officials are considering a slower, less ambitious train system, CNN special investigations correspondent Drew Griffin reports.
In the Northeastern United States, Amtrak operates Acela Express -- a rail service capable of speeds up to 150 mph that shoot riders from New York City to Washington in about 96 minutes.
Responding to critics who say Acela is too slow and too infrequently reaches its top speed, Amtrak plans to run test trains at 165 mph in Delaware, Maryland, New Jersey, Rhode Island and Massachusetts.
High-speed rail critics often oppose it because they say it costs taxpayers too much.
Which is why a proposal in Texas is so interesting.