To solve the problem of soul-destroying traffic, roads must go 3D, which means either flying cars or tunnels. Unlike flying cars, tunnels are weatherproof, out of sight and won't fall on your head. A large network of road tunnels many levels deep would fix congestion in any city, no matter how large it grew (just keep adding levels). The key to making this work is increasing tunneling speed and dropping costs by a factor of 10 or more – this is the goal of The Boring Company. Fast to dig, low cost tunnels would also make Hyperloop adoption viable and enable rapid transit across densely populated regions, enabling travel from New York to Washington DC in less than 30 minutes

Why tunnels?

To alleviate traffic, transportation corridors, like the buildings that feed into them, must expand into three dimensions. One option is to “go up” with flying cars. However, flying cars have issues with weather, noise, and generally increase anxiety levels of those below them. The other option is to “go down” and build tunnels. The benefits are:

  • There is no practical limit to how many layers of tunnels can be built, so any level of traffic can be addressed.
  • Tunnels are weatherproof.
  • Tunnel construction and operation are silent to anyone on the surface.
  • Tunnels don’t divide communities with lanes and barriers.
 

Why hasn't this been done before?

Currently, tunnels are really expensive to dig, with some projects costing as much as $1 billion per mile. In order to make a tunnel network feasible, tunneling costs must be reduced by a factor of more than 10. 

 

How can we reduce the cost of tunneling?

First, reduce the tunnel diameter. To build a one-lane road tunnel, the tunnel diameter must be approximately 28 feet. By placing vehicles on a stabilized electric sled, the diameter can be reduced to less than 14 feet. Reducing the diameter in half reduces tunneling costs by 3-4 times. Secondly, increase the speed of the Tunnel Boring Machine (TBM). TBMs are super slow. A snail is effectively 14 times faster than a soft-soil TBM.  Our goal is to defeat the snail in a race. Ways to increase TBM speed:

  • Increase TBM power. The machine’s power output can be tripled (while coupled with the appropriate upgrades in cooling systems).
  • Continuously tunnel. When building a tunnel, current soft-soil machines tunnel for 50% of the time and erect tunnel support structures the other 50%. This is not efficient. Existing technology can be modified to support continuous tunneling activity.  
  • Automate the TBM. While smaller diameter tunneling machines are automated, larger ones currently require multiple human operators. By automating the larger TBMs, both safety and efficiency are increased.  
  • Go electric. Current tunnel operations often include diesel locomotives. These can be replaced by electric vehicles.   
  • Tunneling R&D. In the United States, there is virtually no investment in tunneling Research and Development (and in many other forms of construction).  Thus, the construction industry is one of the only sectors in our economy that has not improved its productivity in the last 50 years. 
 

What is an electric sled, and why use it?

An electric sled is a flat plate on wheels propelled by an electric motor.  As discussed above, the electric skate allows a large reduction in tunnel diameter, in addition to:

  • Increased safety. A fully stabilized autonomous vehicle eliminates human error and the ability to “swerve off-course.”
  • Increased speed. The controlled autonomous sled allows for speeds of 125 miles per hour in urban settings.
  • Multiple payloads. The electric skate can transport automobiles, goods, and/or people. And if one adds a vacuum shell, it is now a Hyperloop Pod which can travel at 600+ miles per hour.
  • Eliminating hazardous emissions. Electric sleds are zero-emission vehicles, and thus do not output hazardous gases like internal combustion cars do.  Every mile the sled transports a gas-burning vehicle becomes a zero-emission mile.
 

What about earthquakes?

Tunnels, when designed properly, are known to be one of the safest places to be during an earthquake. From a structural safety standpoint, the tunnel moves uniformly with the ground, in contrast to surface structures.  Additionally, a large amount of earthquake damage occurs from falling debris, which does not apply inside tunnels. Some examples:

  • 1994 Northridge Earthquake: no damage to LA Subway tunnels
  • 1989 Loma Prieta (Northern California) Earthquake: no damage to tunnels, which were then used to transport rescue personnel
  • 1985 Mexico City Earthquake: no damage to tunnels, which were then used to transport rescue personnel
 

Is there disruptive surface vibration or noise during tunneling?

No. Once a TBM is below a certain depth (approximately two tunnel diameters – or 28 feet in this case), the tunneling process is almost impossible to detect, especially in soft soil. 

 

What do you do with all that dirt?

In typical tunneling projects, excavated dirt is shipped offsite to disposal locations. This process is costly, time-consuming, noisy, and can be environmentally hazardous. The Boring Company is investigating technologies that will recycle the earth into useful bricks to be used to build structures.  This is not a new concept, as buildings have been constructed from Earth for thousands of years including, according to recent evidence, the Pyramids.  These bricks can potentially be used as a portion of the tunnel lining itself, which is typically built from concrete. Since concrete production accounts for 4.5% of the world’s greenhouse gas emissions, earth bricks would reduce both environmental impact and tunneling costs.