Tag Archives: transportation

I’d like to expand the Jones act so more ships can do US trade.

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If you visit most any European port city, you’ll see a lot more shipping than in the Midwestern US. In Detroit, where I am, your’ll see an occasional ore boat from Wisconsin, and an occasional tourist cruise, but nothing to compare to German, Belgian, or Turkish ports. The reason for the difference is “The Jones act.”

The port of Istanbul with many ships

The Jones act , also known as “The Merchant Marine Act of 1920”, requires that all ships depositing cargo or people between US ports must be US owned, US built, US captained, US flagged, and at least 70% US manned. This raises costs and reduces options. The result is that few ships can move people or cargo between US cities, and these ships are older and less efficient than you’ll see elsewhere. World wide water traffic costs about 1/8 that of rail traffic per ton-mile, but in the US, the prices are more comparable. The original justification was to make sure the US would always have a merchant marine. The Jones act does that, sort of, but mostly, it just makes goods more expensive and travel more restrictive.

The port of Detroit — we rarely see more than one ship at a time.

Because it does some good, I don’t want to get rid of the Jones act entirely, but I’d like to see US shipping options expanded. Almost any expansion would do, e.g. allowing 50% US manned ships delivering along US rivers, or expanding to allow Canadian built ships or flagged, and ships that are more than 50% US owned, or expanding to any NAFTA vessel that meets safety standards. Any expansion of the number of ships available and would help.

The jones act increase the price of oil transport by a factor of five, about.

Currently, the only exceptions to the Jones act are for emergencies (Trump voided the act during several storms) and for ships that visit a foreign port along the route. This exception is how every cruise ship between California and Hawaii works. They’re all foreign, but they stop in Mexico along the way. Similarly, cruises between Florida and Puerto Rico will stop in Bermuda typically, because the ships are foreign owned. Generally, passengers are not allowed to get off in Puerto Rico, but must sleep on board. This is another aspect of the Maritime act that I’d like to see go away.

Because of the Jones act, there is some US freight-ship building, and a supply of sailors and captains. A new, US ore-ship for the Great Lakes was launched last year, so far it’s been used to carry salt. There is also a US built and operated cruise ship in Hawaii, the “Pride of America,” that makes no stop in Mexico. I’d like to see these numbers expanded, and the suggestions above seem like they’d do more good than harm, lowering prices, and allowing modern container ships plus roll-on-roll-off car transports. Our rivers and lakes are super highways; I’d like to see them used more.

The port of Antwerp – far busier than Detroit.

Another way to expand the Jones act while perhaps increasing the number of US-built and operated ship would be through a deal with Canada so that ships from either country could ply trade on either countries rivers. As things stand, Canada has its own version of the Jones act, called the Coastal Trade Act where Canadian vessels must be used for domestic transport (cabotage) unless no such vessel is available. Maybe we can strike a deal with Canada so that the crew can be Canadian or US, and where built ships in either country are chosen on routes in either country, providing they meet the safety and environmental requirements of both.

Robert Buxbaum, June 14, 2023.

The energy cost of airplanes, trains, and buses

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I’ve come to conclude that airplane travel makes a lot more sense than high-speed trains. Consider the marginal energy cost of a 90kg (200 lb) person getting on a 737-800, the most commonly flown commercial jet in US service. For this plane, the ratio of lift/drag at cruise speed is 19, suggesting an average value of 15 or so for a 1 hr trip when you include take-off and landing. The energy cost of his trip is related to the cost of jet fuel, about $3.20/gallon, or about $1/kg. The heat energy content of jet fuel is 44 MJ/kg. Assuming an average engine efficiency of 21%, we calculate a motive-energy cost of 1.1 x 10-7 $/J. The amount of energy per mile is just force times distance. Force is the person’s weight in (in Newtons) divided by 15, the lift/drag ratio. The energy use per mile (1609 m) is 90*9.8*1609/15 = 94,600 J. Multiplying by the $-per-Joule we find the marginal cost is 1¢ per mile: virtually nothing compared to driving.

The Wright brothers testing their gliders in 1901 (left) and 1902 (right). The angle of the tether reflects the dramatic improvement in the lift-to-drag ratio.

The Wright brothers testing their gliders in 1901 (left) and 1902 (right). The angle of the tether reflects a dramatic improvement in lift-to-drag ratio; the marginal cost per mile is inversely proportional to the lift-to-drag ratio.

The marginal cost of 1¢/passenger mile explains why airplanes offer crazy-low, fares to fill seats. But this is just the marginal cost. The average energy cost is higher since it includes the weight of the plane. On a reasonably full 737 flight, the passengers and luggage  weigh about 1/4 as much as the plane and its fuel. Effectively, each passenger weighs 800 lbs, suggesting a 4¢/mile energy cost, or $20 of energy per passenger for the 500 mile flight from Detroit to NY. Though the fuel rate of burn is high, about 5000 lbs/hr, the mpg is high because of the high speed and the high number of passengers. The 737 gets somewhat more than 80 passenger miles per gallon, far less than the typical person driving — and the 747 does better yet.

The average passengers must pay more than $20 for a flight to cover wages, capital, interest, profit, taxes, and landing fees. Still, one can see how discount airlines could make money if they have a good deal with a hub airport, one that allows them low landing fees and allows them to buy fuel at near cost.

Compare this to any proposed super-fast or Mag-lev train. Over any significant distance, the plane will be cheaper, faster, and as energy-efficient. Current US passenger trains, when fairly full, boast a fuel economy of 200 passenger miles per gallon, but they are rarely full. Currently, they take some 15 hours to go Detroit to NY, in part because they go slow, and in part because they go via longer routes, visiting Toronto and Montreal in this case, with many stops along the way. With this long route, even if the train got 150 passenger mpg, the 750 mile trip would use 5 gallons per passenger, compared to 6.25 for the flight above. This is a savings of $5, at a cost of 20 hours of a passenger’s life. Even train speeds were doubled, the trip would still take 10 hours including stops, and the energy cost would be higher. As for price, beyond the costs of wages, capital, interest, profit, taxes, and depot fees, trains have to add the cost of new track and track upkeep. Wages too will be higher because the trip takes longer. While I’d be happy to see better train signaling to allow passenger trains to go 100 mph on current, freight-compatible lines, I can’t see the benefit of government-funded super-track for 150+ mph trains that will still take 10 hours and will still be half-full.

Something else removing my enthusiasm for super trains is the appearance of new short take-off and landing jets. Some years ago, I noted that Detroit’s Coleman Young airport no longer has commercial traffic because its runway was too short, 1550 m. I’m happy to report that Bombardier’s new CS100s should make small airports like this usable. A CS100 will hold 120 passengers, requires only 1509m of runway, and is quiet enough for city use. Similarly, the venerable Q-400 carries 72 passengers and requires 1425m. The economics of these planes is such that it’s hard to imagine mag-lev beating them for the proposed US high-speed train routes: Dallas to Houston; LA to San José to San Francisco; or Chicago-Detroit-Toledo-Cleveland-Pittsburgh. So far US has kept out these planes because Boeing claims unfair competition, but I trust that this is just a delay. For shorter trips, I note that modern busses are as fast and energy-efficient as trains, and far cheaper because they share the road costs with cars and trucks.

If the US does want to spend money, I’d suggest improving inner-city airports, and to improve roads for higher speed car and bus traffic. If you want low pollution transport at high efficiency, how about hydrogen hybrid buses? The range is high and the cost per passenger mile remains low because busses use very little energy per passenger mile.

Robert Buxbaum, October 30, 2017. I taught engineering for 10 years at Michigan State, and my company, REB Research, makes hydrogen generators and hydrogen purifiers.