Why people are excited about Elon Musk’s Hyperloop, and why you should be skeptical

Last March, Paypal and Tesla co-founder Elon Musk's The Boring Company released a map showing a line for a hyper-fast connection between DC and Baltimore. The proposed route traces US-50, the Baltimore-Washington Parkway, and MD-295, and promises to use technology to remedy the ills of urban transportation.

A 15-minute trip between the two cities is an exciting vision, to be sure, and Musk has a lot of fans of his ideas because of his track record of making some of his ideas a reality. Unfortunately, this project likely isn't one of those. The few parts we know about (and we don't know much) neglect some transportation fundamentals.

What is the Hyperloop?

The Boring Company website calls Musk's overall project “Loop,” and describes it as a “high-speed underground public transportation system in which passengers are transported on an autonomous electric skate traveling at 125-150 miles per hour.” However, many people call the project “Hyperloop.” The site says the major difference is that “Hyperloop draws a vacuum inside the tube to eliminate air friction. Loop is used for shorter routes, when there is no technical need to eliminate air friction.” I use “Hyperloop” in this article for simplicity's sake.

Musk envisions that this Hyperloop will eventually connect Baltimore, Washington, and New York City.

So…they’ve invented a high-speed train?

Not quite. The website also describes that future phases of the project would have a widely-distributed network of stations that are the size of a parking spot on the surface. These would ferry passengers up and down between the surface and the underground tunnels.

So… they’ve invented a sort of subway?

Not quite. The ‘autonomous skates’ are car length in size and the stations are envisioned to be ubiquitous enough that no one would have to walk very far to reach one. It would take passengers directly to their destination.

So… they’ve invented an underground bus?

Not quite. Private automobiles, even though they won’t be prioritized, are also able to drive onto the autonomous skates and can be used in lieu of the transit option.

So… they’ve invented underground roads.

Yeah, but they’re really fast underground roads. You really should check out the sweet videos, which are extremely reminiscent Disney’s 1958 “Magic Highway USA” where futuristic vehicles and roadways make anything possible.*

Maybe a network of underground roads is a good thing? Will this open up all of surface streets to pedestrians and bicyclists and the like? Alas, even the promotional video shows a congested road above the tunnel network.

Ok, but why wouldn't this work?

The project as imagined purports to use a new technology to speed up the vehicles and thereby overcome the obstacles that are inherent to public transit. Unfortunately, the constraints on public transit have nothing to do with how fast the vehicles move. An efficient, convenient, and equitable transit system is one that can balance space and cost resources.

Successful transit systems are ones where the vehicles and infrastructure can be used to serve many, many people.** For instance, the same Blue Line route and the same train can be used by people traveling from Alexandria to the Pentagon, by other people going from Arlington to downtown DC, and a third group of people Foggy Bottom to Prince George's County. One vehicle, one route, many people.

It doesn't matter how fast the vehicles are, if people can't share the vehicle and route it is difficult to make transit efficient. Here's a doodle about this:

A transit system that promises access points at every block (or more) and nearly on-demand service is also a system that reduces its ability to share routes and vehicles and requires much more dedicated infrastructure, thereby undermining the benefits that transit can offer.

This is essentially how automobile transportation works. There are roads that connect to all destinations, but it's less common to find two origins and destinations close enough that people would share vehicles.

Ok, but even with all that, this could still be feasible, no?

Let's momentarily suspend our disbelief that this project is nothing more than a way for motorists to avoid above-ground traffic and assume that this project could somehow get around the fundamental issues of providing transit. Is there anything that could actually prevent this from working?

The website's videos and the FAQs answer some general questions about the project, but leave a lot to be desired. Here’s a list of things that need to be addressed:

• Purpose - What is the value of the system? Is it to provide a low-cost mode of transportation into urban centers? If so, it'll be very difficult to keep costs down with all of the necessary construction/operations/maintenance of a system this large. Is the system only for well-heeled individuals who can afford a high speed connection that avoids traffic congestion between Washington and Baltimore? A transportation system can't meet both of those purposes.
• Adequate infrastructure for stations - for every station there would need to be the loading space, the elevator, and additional tunnels for vehicles to accelerate/decelerate. This means that it's not just one tunnel underground, but a series of tunnels to support each station. That's an expensive proposition.
• Limited speed advantage - to reach the proposed speeds, there will need to be adequate distance for the vehicles to accelerate. If a rider's origin and destination were relatively close together, the vehicle couldn't reach the top speed before having to slow down to a stop. If the technology existed where the vehicles could start off at top speed, there would be such a force that people would need to be strapped in and couldn't leisurely stand or sit in the vehicles. The speed advantage that the new technology provides would only be applicable for longer trips.
• Underground traffic - If as proposed, the system is a main artilery tunnel with secondary access tunnels, how will the vehicles be able to maintain high speeds when more and more vehicles are vying for space on the tunnel? As noted above, increasing the access to destinations requires more vehicles, so the limited tunnel space will fill up.
• Crowded underground - It will be difficult to place station elevators and tunnels in existing urban areas because there's already a labyrinth of underground infrastructure including electric utilities, water and sewer pipes, stormwater management tunnels, existing subways, etc.
• Limited accessibility - The proposed route follows the BW Parkway and freeways between the two cities. While this is useful because it is for the most part already publicly owned right-of-way, freeways and the parkway in particular have very limited pedestrian access. How will riders reach the stations? Will new roads be built to reach the stations, will there be parking structures and drop-off loops?
• High costs - Even with the cost savings that the Boring Company promises with its tunnel digging technology, maintaining and operating a transportation system is very expensive, as the current problems WMATA, MTA, and the quality of roads in most places have shown. How will this project be financially sustainable in the long run, especially if fares are supposed to be less than current transit fares?
• Motorists vs. transit - the website indicates that transit vehicles are given priority over private motor vehicles using the “sleds.” How would this actually work if stations are ubiquitous? What keeps this system from being solely used by wealthy car owners?
• Limited above ground space - Even with multiple parking space-sized stations, there will need to be room for people to wait for vehicles ascending and descending the elevators, as well as queueing space for motor vehicles. Cities have already proved that re-allocating roadway space or removing on-street parking for more sidewalks, dedicated bus lanes, bicycle/scooter lanes, or general safety improvements to be a very difficult proposition. These stations will require more space than just the parking space-sized elevator.
• Deeper than 30 feet - The website indicates that the proposed tunnel would be approximately 30 feet below the surface. Some experts have suggested that future phases of the project would have “100 layers of tunnels on top of each other” for multiple routes. However, if each route is layered lower than the preceding, there is a diminishing return on how convenient the route is if you have to travel farther underground to access it. Vehicles might also have to go more slowly to maneuver vertically in the tunnel.
• Drivers' human error - Motorists have a very poor track record of safely operating their vehicles. There will need to be a series of precautions built into the system where people and technology interact. How does the system intend to accommodate human error?

While none of the above issues are technically impossible to solve, it will require cities and their residents to adapt dramatically to the new system. Most places will have to make substantial changes to their built environment just to get the system functioning. At what point is the city being rebuilt to suit the needs of the transit system, instead of the transit system working to suit the needs of the city and its riders?

Is it all a wash?

While this Hyperloop project does not make for a realistic or workable transit system, a fast, direct transit line between Washington and Baltimore with an eventual extension along the east coast is a reasonable project. But don't think of it as a new disruptive technology; it's an update to the Amtrak Acela. In fact, there is already another project trying to do exactly that: The Baltimore-Washington Superconducting Maglev Project.

Unfortunately, this won't be the end of companies trying to woo cities with new technology to solve seemingly intractable transportation problems. Turn-key solutions are very appealing, especially to elected officials, because the best solutions are a difficult political sell.

Bus service could be exponentially improved in both time and convenience if all bus routes had dedicated lanes and didn’t need to travel in mixed traffic. Commuter rail could be more convenient if there were higher frequencies. Faster travel times are great, but the transit is more than just time spent inside the vehicle.

The Boring Company claims it can built an entire network because it can build the tunnel infrastructure faster and at a lower cost. I sincerely wish them success in this. Tunneling is expensive and time consuming and is often the obstacle to expanding existing networks; they should work with existing transit agencies to improve transit.

It doesn't matter how well you can bore tunnels, a transit system that is solely based on new technology without addressing the fundamentals of transit is just digging yourself deeper.

* This cartoon is wildly prophetic in some instances and illustrative of the same futuristic technologies that are perennially promoted today, like this, this, and this.

** An excellent primer on how public transit functions is Jarrett Walker's Human Transit.