mindstalk: (Earth)
I've been reading a bunch of kchoze posts the past couple days. This one is on the economics of transit, and transit efficiency.

'if transit is economically inefficient, why are third world cities dominated by transit and not by personal cars? Why do the Japanese pay 10% of their income on transport versus 20% for Americans and Canadians?'

There are some numbers, and discussion of cost per mile vs. cost per trip. But there's one thing which I sort of gut felt that he spells out: transit friendly cities are denser, so they're more walkable as well.

Let me spell that out. In a sprawling car-centric city, up to 100% of trips may be taken by car. Actual numbers are more like 90%. [Caveat: that's share of trips to work, not all trips.] But you'll never see a city that's 90% transit mode share. (Some cities listed do get up to 70% transit, but again, that's commuting to work.) A city that has lots of transit is a city with lots of walking, too, especially if uses are decently mixed.

(I'm sort of imagining a degenerate case where there's no point to walking around one's residential neighborhood, not even for groceries or school or church, and having to catch transit elsewhere...)

So the reasonable target is not getting transit share really high, but car share low, with the slack being taken up by a mix of transit, walking, and bikes.

This has an extra economic effect: in Sprawlville, the cost of cars (roads, parking, cars, gas...) can be spread over almost all trips. Naively, the cost per trip of transit is doing to have a smaller denominator, only 40% of trips rather than 100%, even though the other non-car trips are part of a coherent dense system that must include transit.
mindstalk: (Default)
after 15 million miles traveled, the Citibike program has still caused not a single fatality for either pedestrians or riders, and fewer than 30 serious injuries, while helping to improve the overall safety of the city’s streets.

In each of these cases, a thoughtful, intelligent observer is prodded by a mix of fear and anger to give an alarming anecdote more weight than an abundance of evidence, or even common sense. On a street carrying thousands of 3000 pound vehicles a day at 40mph or more, we focus our fears on the handful of 30 pound vehicles moving half that fast.

The CDC reports that 59,925 pedestrians were killed by motor vehicles between 1999 and 2009, while bikes (which are used for about 1.6% of all trips in the US) killed 63 in that same period, or roughly 0.1% as many.

drivers do rolling stops too
A 2002 study by England's Transport Research Laboratory found that when bicyclists violated a traffic law, motorists saw it as symptomatic of reckless attitudes and incompetence among people who choose to bike. However, when they saw another driver breaking the same law, they tended to see it as somehow required by unpredictable circumstances.

Hyperloop hype

2013-Aug-16, Friday 23:02
mindstalk: (Void Engineer)
Is Elon Musk's Hyperloop proposal just massively naive, the result of an arrogant superstar who thinks he can wander into another field without doing the research, or an attempt to sabotage the HSR project?

Proposal doesn't actually connect SF and LA, but the east Bay and Sylmar. "Amusingly enough, the California HSR budget for the Central Valley is under $10 billion. Ie, in the same ball-park as this proposal. The reason the HSR project is going to cost $60 billion is because it has to face an uncomfortable truth; actually getting to LA and SF is expensive." Given this, the "35 minute" travel time is also wrong:

"Hyperloop trip between downtown LA and downtown SF:
1 hour from LA to Sylmar via Metrolink
20 minute transfer
35 minutes to Dublin
20 minute transfer
1 hour 10 minutes from Dublin to SF via BART

Total: 3 hours 25 minutes"

If you do build into SF and LA, you're talking about multiple multi-billion dollar costs: urban right of away, stations, Bay crossing...

Proposal also ignores NIMBYs and lack of enthusiasm for aerial structures blocking views. And ignores politics: proposal has no stops between SF and LA, a good way to lose votes. It's politics that has HSR using viaducts (like Hyperloop!) and building connections to every major city it can.

"Should we trust that man who claimed that California building the world's slowest bullet train (false) and the world's most expensive rail line (also false) as his inspiration?"

0.5g is more like a roller coaster, less like an elevator or subway. Realistic acceleration means longer sections.
"Show Stopper #7: There is little in the document that discusses the cost, size or weight of environmental control and life support systems" "This vehicle subsystem would not be unlike a business jet’s environmental control system, which is neither small, simple, light-weight, nor cheap."
How do you do branching or intermediate stops? How do you do maintenance without shutting down the whole system?
Headway calculations seem naive.

"My specific problems are that Hyperloop a) made up the cost projections, b) has awful passenger comfort, c) has very little capacity, and d) lies about energy consumption of conventional HSR."

"In principle, Hyperloop is supposed to get people from Los Angeles to San Francisco in half an hour, running in a tube with near-vacuum at speeds topping at 1,220 km/h. In practice, both the costs and the running times are full of magic asterisks. The LA end is really Sylmar, at the edge of the LA Basin; with additional access time and security checks, this is no faster than conventional HSR doing the trip in 2:40. There is a crossing of the San Francisco Bay, but there’s no mention of the high cost of bridging over or tunneling under the Bay – we’re supposed to take it on faith the unit cost is the same as along the I-5 corridor in the Central Valley."

"There is no systematic attempt at figuring out standard practices for cost, or earthquake safety (about which the report is full of FUD about the risks of a “ground-based system”). There are no references for anything; they’re beneath the entrepreneur’s dignity. It’s fine if Musk thinks he can build certain structures for lower cost than is normal, or achieve better safety, but he should at least mention how."

"In reality, an all-elevated system is a bug rather than a feature. Central Valley land is cheap; pylons are expensive, as can be readily seen by the costs of elevated highways and trains all over the world."

Some paragraphs about accelerations, again comparing Musk's numbers to a roller coaster or barf ride, far higher than real rail systems.

"The proposed headway is 30 seconds, for 3,360 passengers per direction per hour. A freeway lane can do better: about 2,000 vehicles, with an average intercity car occupancy of 2. HSR can do 12,000 passengers per direction per hour: 12 trains per hour is possible, and each train can easily fit 1,000 people (the Tokaido Shinkansen tops at 14 tph and 1,323 passengers per train)."

"The chart has a train consuming nearly 900 megajoules per person for an LA-San Francisco trip, about as much as a car or a plane; this is about 1,300 kJ per passenger-km. This may be true of Amtrak’s diesel locomotives; but energy consumption for HSR in Spain is on average 73 Watt-hour (263 kJ) per passenger-km (see PDF-page 17 on a UIC paper on the subject of HSR carbon emissions), one fifth as much as Tesla claims. Tesla either engages in fraud or is channeling dodgy research about the electricity consumption of high-speed trains."

"I write this to point out that, in the US, people will treat any crank seriously if he has enough money or enough prowess in another field. A sufficiently rich person is surrounded by sycophants and stenographers who won’t check his numbers against anything."

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