Executive Summary: Hyperloop won’t be as cheap as they say
Safety costs money. Cars used to be cheaper to build when they didn’t have as much metal, airbags, and antilock brakes. Hyperloop will be no different. Your ride won’t be as cheap as the press announcements you read in 2016.
The example of air transport
The airliner has gotten progressively safer in absolute terms since 1972. Indeed, we haven’t seen a fatal airline crash in the US since 2009. To achieve this level of safety took a century of experience. In that same period, reliability increased and fuel consumption decreased. Whether this is the result of commercial competition or government regulation is a matter for discussion. What is clear is that US airlines are willing to hang their hats on the FAA “single level of safety”. Each is satisfied to have a comparable level of expense to its competitors and a third party to which to point. If a higher level of safety were of interest to travelers, some airline would have stepped out, spent more, and made advertising claims. None has. There is tacit agreement among airline not to make safety claims. The closest an airline has come was British Airways, which claimed it was “the world’s most experienced airline”. No other airline has ever advertised safety. A string of accidents is hard to predict even for a relatively safe operator; such an advertising campaign could easily backfire.
Even the FAA recognizes the cost of safety. In its system safety approach it provides this graph.
This graphic is illustrative, as far as it goes. It is not supported by empirical data, as similar graphs in an economics textbook are. It bears an amazing resemblance to speed vs drag curves found in pilot training.
No one quite knows the shape of the cost of safety programs curve for Hyperloop. The cost of accidents is a question for insurance companies, who deal with the cost of accidents after they happen. When budgeting for safety prior to an accident, the FAA uses a concept called Value of Statistical Life (VSL), the amount that is reasonable to spend to prevent the loss of a single life. A high VSL can be used to justify large spending. When there is no baseline “typical number of fatalities per year”, using VSL to justify spending is an exercise in palm-reading.
The Hyperloop tube, a “confined space” by OSHA definition, is a hazardous place. We looked at the risk in this post. The vacuum proposed by Elon Musk’s white paper is far more dangerous than the altitudes at which the FAA allows a civilian airplane to fly. There will be some expensive engineering required to make a capsule that can reliably transport passengers with pressure suits and oxygen masks.
Almost all of the Hyperloop failure modes lead to an environmental risk. A stopped capsule, a punctured tube, or a failed capsule door eventually lead to a potentially fatal event.
If Hyperloop has any hope to compete with California High Speed Rail, it will need to traverse the most seismically active area in North America. Hyperloop advocates have described a system of slides and dampers that would tolerate seismic shift and thermal expansion. The seismic risk is one reason why the first Hyperloop is likely to be outside the United States.
Phil Mason PhD published this video highly critical of Hyperloop. He describes the thermal expansion of a 600 km tube in the extreme of California weather as 300 m. Design of expansion joints is a challenge, but one that the petroleum industry solved already. An oil pipeline operates at a pressure on the order of 750 psi (5.2 million Pascals). The Hyperloop tube will need to operate at a pressure differential of 14.7 psi (100,000 Pascals), 1/50th the difference. Given that pipeline builders have solved this problem already, at much higher pressures, this is is not the highest hurdle for Hyperloop.
A Hyperloop capsule can’t pull to the side of the road if a passenger feels sick. The situation inside a capsule will be the same as on an airplane. If a passenger has a heart attack, other passengers will use an AED and wait for the next stop. It’s only a half hour away.
Airplane manufacturers and airlines didn’t worry about threats to safety from bad actors until a spate of hijackings 1969-1972. The events of 9/11 led to a more-or-less permanent commitment to airline security and creation of federal agencies devoted to secutiry. In 2013, TSA spending on airline security was $8 billion.
Hyperloop operators should expect the TSA to take a great interest in this new form of transport. It will point out that a threat can be introduced anywhere along the route, not just at the original terminal.
The best analog in this case is petroleum pipeline sabotage. In North America, these events are rare and seldom damaging. Three pipeline bombings in Canada in 2009-9 caused damage, but not pipeline rupture or fire. In 2001 a hunter, likely drunk, shot a hole in the Trans-Alaska pipeline. The bullet punctured the pipeline, causing a spill of 285,000 gallons of crude oil. Whether a similar attack on a Hyperloop tube would lead to a catastrophic failure is currently unknown. The pipe currently being used for Hyperloop tests is thicker than oil pipelines. If punctured, it is likely that system vacuum pumps could out-pump the air flowing through a one inch hole. An anti-tank round is another story.
Of more concern is the inconvenience of passenger screening prior to a half-hour trip from Los Angeles to San Francisco. Delays to Hyperloop passengers of the same order as for airline passengers could wipe out any meaningful time savings.