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Car tires biggest likely source of microplastics in California coastal waters (latimes.com)
198 points by lnguyen 14 days ago | hide | past | web | favorite | 222 comments

This is one reason why I don't like living near freeways, especially near on-ramps, off-ramps, and interchanges. Car pollution isn't just tailpipe emissions - I believe a lot of airborne particulates come from tires and brakes (especially during acceleration, deceleration, and turning).


Cody's Lab did an episode where he collected and refined freeway dust: it's actually decent grade platinum 'ore' from catalytic converter deposition


Sure, in small quantities, it's not the majority of the volume they collected though.

Mining operations rarely find pure metals in the ground. Ore is a dilute mixture of rock with trace metals which must be extracted through processing.

To categorize what's found on the shoulders of highways entirely as an ore of some trace metal is to completely dismiss the rest of its content as irrelevant, despite being the bulk of its volume, in a discussion ostensibly about pollution.

California air quality regulators have stated that we shouldn't have any housing within 500 feet of freeways. Living near freeways increases your risk of a host of negative health effects (asthma, heart issues, etc).


Maybe California should worry about having adequate affordable housing before worrying about where said housing is located.

yeah fuck em, lets just put them next to the oil distilleries in Richmond. freeway and air pollutants.

A cheaper home next to a freeway is probably healthier than living on the street.

Came up in conversation when I took my car in that up until recently they were using little bits of copper in brake pads for... noise control? heat? I can't recall which.

But that's been outlawed now, presumably due to potential for metal toxicity (any mineral you need in your diet is also lethal at higher doses). We're leaving powdered copper at every stop light.

Copper is still very common in brake pads, both in the semi-metallic and ceramic varieties. California phases out copper-containing brake pads starting in 2025.

Now that you mention it I think he did mention California. It's entirely likely he said "are banning" and I took that as present tense and not future tense.

Copper is used as bottom-coat on sailboats, it's also used as a non-hormonal contraceptive IUD material.

I don't think it's terribly harmful for humans if it's safe for a women's uterus. California tends to be exceptionally concerned for the environment in general. All that copper dust making it into the coastal marine environments isn't going to be good for it, considering the same stuff is used to keep marine life off boats.


"The issue has been under consideration since the 1990s, when cities south of San Francisco were having trouble meeting Clean Water Act requirements to reduce copper in urban run-off flowing into San Francisco Bay. Preliminary studies indicated that brake pads were a significant source of copper in that runoff. Tiny amounts of copper fall onto the streets and parking lots every time drivers step on their brakes."

from https://www.copper.org/environment/impact/copper-brake.html

As I suspected, it doesn't appear to be primarily a human toxicity concern. It's to protect the marine environment.

Weren't brakes made of asbestos at one time?

Canada banned asbestos brakes this year. Brakes are still exempted under US asbestos bans. Manufacturers and repair shops avoid them for obvious reasons, but they're not illegal.



they were. But they used asbestos in a lot of things back in the day. I worked in a building with asbestos in the floor tiles. When they did constructions that involved removing the tiles, it became a big deal.

Asbestos isn't that harmful, until it goes airborne. My understanding from research (I worked expanding a landfill that took asbestos at one point). is that the particles are too small to be caught by our bodies defenses and when it ends up in your lungs its cancerous. Asbestos in brakes seems like a bad idea.

see: https://en.wikipedia.org/wiki/Mesothelioma

There's another thread that claims that was 50 years ago.

I believe a lot of the stopping power comes from ceramic cinders in the pads. Those showed up in high end bicycle brake pads about 25 years ago, and I think they were old news in high performance cars before that. I have a fuzzy recollection that they trickled down into mid-tier vehicles not long after that. 2000-ish?

Yes. Napa and other brake manufacturers are called into lots of mesothelioma trials. Brake pad exposure is usually smaller contributors to such cases. That is, the victim often had much worse exposure other places, but they still look at how much brake pad exposure the person had too.

I don't know about copper in particular, but metallic content is very common in sport or racing pads for additional 'bite' (higher friction) and heat tolerance.

I once had to wait at a bus stop right next to the 405 in Los Angeles for a good 30 minutes. It felt like being suffocated.

Up until 97(?) brakes used to be lined with asbestos. It wouldn't surprise me if there is a detectable amount close to highways as well.

You don't want to live within 5 miles of a freeway or major road really..

The airborne particulates from brakes is asbestos!

edit: Very odd that both mine and the contradictory reply to it are both down voted. What I said is a fact, so I'm not sure why anyone would disagree with it.

This hasn't been the case since the early 80s.

Edit: Yes, you can probably find some no-name pads with asbestos if you look hard. Nobody is selling them knowingly in the US or EU. There are definitively some pads/shoes from the far east that contain asbestos. They don't get purchased by the auto parts stores and big parts suppliers that supply the shops that change most of the countries brakes. They get sold to importers who don't care what they're made of who are selling them on Amazon/Ebay/etc to DIYers at bottom dollar prices. That is such a tiny slice of a tiny slice of all pads it's basically nonexistant.

Ford was shipping cars with asbestos brakes in 1993. Asbestos brakes are still readily available on the aftermarket.

Brake pads since 2015 sold in California and Washington must have less than 0.1% asbestos by weight (it's unclear to me if that's asbestos alone, or asbestos and other heavy metals like cadmium or mercury). Since the ban was put into place in 2015, you can reasonably infer a) that there were brake pads above that limit in 2014 and b) there are brake pads slightly under that limit today.

the subway brakes in washington dc are abestos brakes. you can smell them quite strongly.

Can you really smell asbestos? I can't imagine silicate rock having a very high vapour pressure.

That is not correct. WMATA hasn't used asbestos brake pads in many years. Whatever you think you smell, that's not it

Considering the smell from brakes in subways and freight rail yards is the same as burned brakes and clutches on modern vehicles (which do not use asbestos) I am going to need a citation for that.

"Asbestos was used on Metro's cars when they first started running in 1976, but only a few of the asbestos pads remain in service." - written in 1980 in Washington Post - see link in sibling comment.

Huh, TIL. Never knew what that smell was.

According to the Wikipedia article[1] for the company mentioned in one of the other replies to this comment:

> The Raymark facility operated at (the Stratford) location from 1919 until 1989, manufacturing asbestos brake linings and other automotive asbestos products.

so it hasn't been true for 30 years. :)

[1]: https://en.wikipedia.org/wiki/Raybestos#Superfund_site_clean...

Without sarcasm, what are "raybestos" brakes made out of then?


Thanks all for the clarification.


Apparently the company hasn't produced a product with asbestos in it since the 80s.

Not asbestos and haven't been for decades. They actually have something like "contain no asbestos" on the box (or maybe it's on a piece of paper in the box, it's been awhile).

Tangentially related; I can't fathom why the US insists on stop signs and traffic lights everywhere. A neighborhood I used to drive through on my way to work had 4 way stops sprouting up constantly.

The massive waste of resources involved in hauling 2 tons of steel and glass down from speed to 0, for _absolutely no reason 99% of the time_, accelerating it back up to speed again, just to do the same, over and over, boggles the mind. The noise pollution, the air pollution, the "trash" byproducts in the form of brake dust and tire dust. Why on earth would you voluntarily do this to your neighborhood? It doesn't stop speeding; it's a crappy form of traffic control, and it makes every traffic-related measure of living near it worse. Add to all that the time wasted. I feel the same way about traffic lights, particularly the over-proliferation of red arrows everywhere, telling us that we can't judge for ourselves when it's safe to go, and instead, we have to create gridlock and extensive waits for minimal gain.

Most of these problems could be solved by keeping traffic at a moderate, consistent level through the use of roundabouts, rather than the waste of constant stop-and-go.

When I rule the world, there will be a ban on 4-way stops, red arrows, and parking lots without walkways. I don't even have kids, and I find it infuriating that parking lots force us to walk behind rows and rows of parked cars, hoping that we don't get run over by someone backing out of a space in one of the ever-increasingly-difficult-to-see-out-of cars we're bringing to market in the name of 'safety'.

> I can't fathom why the US insists on stop signs and traffic lights everywhere. A neighborhood I used to drive through on my way to work had 4 way stops sprouting up constantly.

I don't mean to sound snarky or judgemental, so please understand that is not my intention... Sometimes they do this to dissuade people from commuting to work through neighborhoods. Again, I don't mean to judge, that might be the best/safest/only/etc way for you to get to work and you may not be the target of these stop signs.

There is a 4 way stop in my neighborhood that is going to be converted to a traffic circle next year to keep traffic moving. Waze currently routes a lot of traffic through our neighborhood when the freeway is backed up at rush hour. I think the traffic circle might make it worse since the "pain" of the 4 way stops will be gone so the backup might be gone but the traffic volume would be higher. I might be wrong, but I'm curious to see the final effect. I'm also not sure which is worse for overall health and safety -- the higher volume with no bottleneck or lower volume with a bottleneck.

I may be being a bit of a pedant but do you mean roundabout? Traffic circles and roundabouts are different. A traffic circle, in the modern sense, does not have much horizontal deflection on the entering legs. The diameter is also smaller and there is not a truck apron. A roundabout on the other hand has some form of horizontal deflection and a truck apron. Often times a traffic circle can be installed by placing a round bit of curbing in the center of an existing intersection. These are great in low volume low speed applications such as neighborhoods. Traffic circles have a much lower capacity than a roundabout due to the low travel speeds.

Again, sorry for being a pedant but I am a traffic engineer and the distinction between these two traffic control devices matters. Here is a link to roundabout specific information from the Federal Highways Administration https://safety.fhwa.dot.gov/intersection/innovative/roundabo...

>the distinction between these two traffic control devices matters

To reflect your pedantic efforts: does it matter in _this_ discussion? Colloquially they are the same thing when not having a technical discussion.

Traffic circles and roundabouts don't exist. Those things are all called rotaries. The tiny ones are inherently defective, especially for large vehicles. The larger rotaries can be nice, especially when installed above a freeway that intersects with low-volume roads, but they are too costly unless the land is very cheap.

A decent use of a rotary is in Massachusetts where Drum Hill Road and Old Westford Road meet US 4 (North Road) right over top of Interstate 3. It's a 6-way intersection, with the elevated rotary helping to deal with the high speed of Interstate 3. The intersection used to be even nicer, free of traffic lights and with a smooth elliptical shape, prior to Interstate 3 being widened.

A rotary has higher speeds and entering traffic gets the right-of-way. They are very different from a roundabout.

Surely you mean US 3 and MA 4

You are correct, it is technically a roundabout. $1.3 million for a single lane roundabout with a raised median. Does that cost sound reasonable?

It really depends on the agency building the roundabout and the property values at the intersection. For example a rural intersect near me just got a single lane roundabout and it cost $3.2 million. The agency building it prefer a lot of concrete over asphalt. Other states can build them for less if they use asphalt.

No worries, and I understand your concern. Yes, there is a neighborhood arterial (2, actually) as the only routes to the office park. To be fair, they're arterials with 30mph speed limits (no driveways on them), which, frankly, makes the stop signs all the more galling. (they were specifically called out in a traffic study of that neighborhood as the WRONG way to control traffic on that type of road).

> The massive waste of resources involved in hauling 2 tons of steel and glass down from speed to 0

Even without slowing down this is huge waste of resources. The fact we allow people to do this is insane.

> When I rule the world, there will be a ban on 4-way stops, red arrows, and parking lots without walkways.

You are insane if you think you can make cars safe. They should just not be around people at all.

Yes, somehow whenever these issues come up, it never leads to a suggestion of banning cars. Instead, there is an "angels on a pin" dissection of some obscure details that will supposedly fix the problem but that completely misses the point: cars are killing us all (pollution, carbon, obesity, degradation of city life) and need to be generally rejected for common use.

Round abouts dont reduce evergy use much. If you reduce speed by 50 percent, you've still converted 75 percent of your kinetic energy to heat. I agree that many of the stopsigns are not needed.

We could recover the energy.

mgh = 0.5mvv

Cancel out the mass, round g to 10 m/s/s, assume a velocity of 30 m/s, and solve for h:

h = 45

We thus need a rotary that is elevated 45 meters above the road. That is about 150 feet. This could work for a highway, especially if it is in a road cut.

I prefer stop signs to roundabouts. In Ireland, I experienced several low-radius roundabouts in succession, and they always made me nauseous.

If roundabouts are made large enough to be pleasant, they are fine but take up a lot of space.

I'm very impressed with countries that slow down traffic by making the street a little narrower.

"A scientific review of 52 studies recently concluded that humans on average consume a credit card’s worth of microplastic each week."


As shocking as that is, I'd like to see some confirmation of that number.

I don't doubt the analogy, but I think we need to study if this is actually harmful. Does the body expel it entirely as waste, or is some left behind, etc.

It must expel it to a high degree. I can't imagine any significant amount of 52 credit cards worth of plastic a year being retained by the body. That would mean that I have approximately 1500 credit cards worth of plastic in my body just layin' around after my 29 years of livin'.

I can tell ya - I'd notice 1500 credit cards worth of plastic hanging out in my body. That's 5g * 1500 = 7.5kg (16.5lbs) of plastic.

We used to think that trace amounts of pesticides in our food supply was perfectly safe.

Can someone tell me why microplastics are actually bad? I feel like scientists have recently been discovering they're everywhere, but is there any negative effect? They really are everywhere, and theres nothing we can do now.

I bought a Patagonia fleece the other day, and realized the thing is practically made out of microplastics, or 'recycled polyester'. And Patagonia claims to be an eco-friendly company, even though they acknowledge the microplastics problem.

Interesting, considering just a few decades ago bundling old tires and sinking them into the ocean was considered an environmentally-friendly disposal method.

It was believed that the tires would create reefs, encouraging sea life, and at the same time take care of on ongoing tire disposal problem that occasionally led to catastrophic fires.

I wonder what other modern "environmentally friendly" things we're doing now that will turn out to be bas ackward 30 years from now.

Well, if you pay attention, it sounds like we're discovering plastic recycling falls into that category.

It even fits the part where we really wanted to believe it, so it wasn't hard to convince ourselves.

Using old railroad ties for landscaping, building things in gardens, parks and playgrounds. They are impregnated with some nasty stuff which outgases when lit by the sun. Which happens to be the time people are mostly around them.

Tires & asphalt "wear" aka become abraded into dust that has to go somewhere

that could well be fine, because those tires aren't abraded into small particles the same way?

The problem is it often isn't fine: the tires are not stationary: as the waves drag them around on the sea floor they do significant damage to sea floor structures that can stand waves by not something more solid.

Nature can erode anything with enough time, rubber is no competition.

I appreciate this new concern for microplastics. Since I can remember I've always had a vague fears about using plastic Tupperware and plastic bottle but wasn't sure if it was unfounded. Turns out my (and many others) intuitions were correct.

Is there evidence that Tupperware breaks down and gets into food that you store inside it?


> Most Plastic Products Release Estrogenic Chemicals: A Potential Health Problem That Can Be Solved

> Results: Almost all commercially available plastic products we sampled—independent of the type of resin, product, or retail source—leached chemicals having reliably detectable EA, including those advertised as BPA free. In some cases, BPA-free products released chemicals having more EA than did BPA-containing products.

(DISCLAIMER: I am hoping we can discuss this from a purely intellectual perspective and not bring ideology into it)

I have always postulated that the increase of estrogenic compounds may have some impact on what seems to be an utter surge of reported cases of gender dysphoria amongst others other disorders that typically arise when you mess with hormonal/endocrine systems. Has there been any scientific research done on this topic or is just viewed as an untouchable subject due to fear of backlash (which would be a shame if so)? It's no secret by now that we have been consuming large amounts of estrogenic compounds now in large amounts, whether it is indirectly through plastics and other industrial compounds, hormone-filled meats and dairy, other animal by-products, prescription of hormones, or more directly through the over-prescription and overuse of hormones and other drugs that have a pseudo-hormonal effect on our brains such as steroids (there is even hormones in our drinking water!) I just wonder if we are barking up a tree we have so little understanding of.

As an anecdote, I as a male suffered from gynecomastia. I did a lot of research. I learned what once used to be almost always guaranteed to be denied by insurance because it was considered purely cosmetic, is now so common insurances felt the need to cover it. So the insurance companies seem to have even caught whiff of something being "in the water" so to speak.

I wonder if we will look back in 50 years, just like some of us can point back and say about our grandparents and great grandparents generation and say "oh yeah it was all that lead you were exposed to which caused all those adverse effects (health-wise, personality-wise, and IQ wise)" if we will point back and say "oh yeah it was all those hormones or hormone disruptors you pumped into everything"

There are so many things that have changed in the last 50 years that there is a a large surface area of changes that could be causing mass hormone imbalance.

Plastics, daily dairy consumptions (every meal!), soy, sedentary lifestyle, processed food, lack of minerals in soil/food, not being exposed to natural fungus in soil and nature, not consuming enough fermented foods because we have refrigeration, not enough meditation we would get from sitting in front of a fire, not enough exposure to heat/cold in the natural seasons, not using natural ground water... obviously not all of that, but my point is that it could be anything.

Dunno about the benefits of fermented food: oxidized nitrates ain’t great for you.

negative properties doesn't mean there aren't any beneficial properties. maybe fermented food are good for our gut biome or something, which impacts our metabolism and fat levels, which impacts our hormones levels, idk. you're missing the point.

I would expect if that were the case that you’d see a disparity in the number of MtF compared to FtM. And the MtF to FTM ratio is according to the NIH 2.2:1, which is pretty significant

(Although now I’m reading the methodology behind that number may be flawed)

It's accepted that male fertility rates are lower than in the past in the developed world, but further to that I recall reading that it also applies to our dogs, who are exposed to many of the same environmental factors despite a different diet in many cases.

My "intellectual perspective" on this theory that you just made up is that you just made it up. Have a nice day.

Well yes. It is my theory. I did make it up, formulating my own hypothesis. What is your point?

I was just floored when the BPA problems arose and all these people I knew were trading in one plastic bottle for a different one. I'm switching to glass and stainless and everyone else is buying more plastic.

Just... don't understand why we learn so slow.

Plastics are just pretty damn convenient materials. They're solid, cheap, can be made flexible or hard, don't rust, are easy to clean etc... Glass is heavy and breaks when dropped, metal is less heavy and only dents but it's more expensive than plastic. A lot of metal containers have an internal plastic lining simply so that food (and especially acidic food) doesn't react with the metal through direct contact.


Once in a while I'll see something about the history of food preservation and it's always funny because the more optimistic folks will point to a particular date and inventor as the birth of pasteurized canning. And then a more curmudgeonly person will sometimes point out that the tin from those cans would leach in and turn the food black.

Not quite the victory people make it out to be. It was a bit later before they got the process to store food that people would eat.

This is a tangent but I liked this video on beverage cans, https://www.youtube.com/watch?v=hUhisi2FBuw

I've always been leery of metal containers because I'm sure there's some unsafe machine oil/lubricant in there from the China manufacturing plant it was made at and wasn't completely/properly washed. Even after washing it at home I'm sure you can't get everything out.

I can do you one better. During that time frame, Kleen Kanteen made a big mea culpa, because initially they claimed that their canteens were BPA free and then they found out they were lining them with... you guessed it, BPA.

I tend to use glass for anything other than water. Anything without a neutral pH can make your container more reactive, no matter what it's made of. I put tea or coffee into a double wall stainless, but only occasionally.

Do you have a source on the Klean Lantern BPA? I have some bottles and want to find out if they are lined this way.

What's wrong with ceramics?

I use ceramics around the house all the time, but I was trying to limit my comments to storage and transportation.

Of course I have a friend who found some ceramic food storage containers with lids. They're lighter than glasslock but I already have more than I use, and they have better seals.

Ceramics are sometimes finished with a lead (or other heavy metal) based glaze. If that is the case your have problems much more serious than BPA was ever accused of. When you buy souvenir plates you often see "not for food contact" or other such language - the finish is why. (note, sometimes the finish is safe but the factory does other things that are not safe and don't want to do better purification of the equipment between runs)

It sounds less unreasonable if you realize that "plastic" is about as specific as "crystalline" or "brittle".

I feel the same way, especially about flame retardants.

   1: discover they are poison
   2: invent a new one
   3: ten years pass
   4: GOTO 1

The expert interviewed here agrees with you.


Big fan of this channel in general, he at least tries to back up his research (there's a recent one on the perceived danger of overheating non-stick pans).

I wonder if there's a point where the leaching greatly diminishes after so long (b/c everything from the surface has leached).

For instance, I'd like to know if my hard-plastic Camelbak water container is now basically safe considering I've had it for about 4 years and refill it about 2/3 times a day, or if it's leaching at essentially the same rate as when it was new.

Or perhaps it leeches at a higher rate as the plastic physically and chemically degrades. Would be worth looking into.

Yes, indeed an interesting question

The dose makes the poison. Saying there are detectable levels of BPA doesn’t tell you much when the lower detection limit is parts per billion or parts per trillion.

It's soft. I have old Tupperware right here in my kitchen that has frayed surfaces and little bits and pieces must get into food.

Just think about the amount of plastic in foods from plastic cutting boards or using metal utensils on non-stick coated bans (with whatever kind of crazy chemicals are in there).

Non-Stick coating is pretty inert around room temperature, the real problem with them is if you heat them up too much which happens easily. They start to release all kinds of highly toxic gasses.

What were your intuitions?

Right now the research seems to show plastic micro particles show up in a lot of places, but whether that actually causes harm remains to be seen.

Intuition was that I am ingesting plastic or chemicals that leech out of the plastic when using plastic containers. I don't need evidence as to whether that actually causes harm. I need evidence that it doesn't cause harm. I prefer not to ingest artificial substances unintentionally.

I'm guessing the vast majority goes through the digestive tract without any issues, and whatever ends up in our bloodstream gets filtered out like anything else in our system. Personally, I'm not worried about it.

I definitely think it's something that should be studied more though.

in atlanta soil near roads tends to have a lot of lead. A daycare near me had to shutdown their playground/garden because it was testing really high in lead.

Where was this in Atlanta? I only remember this story and it was not because of car pollution.[1]

> The EPA believes the lead came from fill material used by the neighborhood's original developers to level out some of the lots more than a century ago.


soulshine decatur. Not sure it made the news.

Why does it have lead?

Because of leaded fuel and the principle of conservation of species and mass. Every atom of lead that ever passed through an American gas pump is currently laying around on American soil.

Lead used tp be a very common additive in gasoline. In the US there was no legislation to reduce it's use until the 1973 and it wasn't fully banned until 1996.

It can be assumed that any well-trafficked road during or before this period has substantial lead contamination.

It's still allowed in general aviation. Let your lawmakers know if that bothers you. The stakeholders in this case happen to be a small, wealthy minority.

Wealthy on a global level definitely, but as far as Americans go there are lots of relatively normal middle-income hobbyists in GA. You can buy and operate a plane for less than a used car if you're frugal about flying.

Probably from tetraethyl lead, which wasn’t banned in common fuels until the 70’s in the US.

That said, there are enough other sources of lead (e.g. old paint) that this isn’t guaranteed to be right.

Probably from tetraethyl lead, which wasn’t banned in common fuels until the 70’s in the US.

Except in California, which had leaded fuel well into the 90's for rich people's collector cars. Another example of the do-as-I-say-not-as-I-do sorts of things that happen in California.

Yep, California banned leaded fuel for automotives in 1992, 4 years before the United States federal government followed up.


Don't forget all piston powered aircraft flying today!

I think because of train tracks everywhere

I'm sure the playground also had the traditional padded floor made out of recycled shredded tire pellets.

all I can think about now is the total surface area of plastic in the world rubbing against something and being ground into microplastic dust

What are the negative effects of microplastics?

Are tires made of plastic?

From the article:

>Rubber is also considered plastic, both natural (isoprene) and synthetic (styrene butadiene).

Definitely not what comes to mind when I think of plastics. I usually hear Bakelite quoted as the first invented plastic.

Think "polymer" or "synthetic polymer" since these will be the things bacteria and other parts of nature have not evolved around.


Synthetic rubber was, in fact, invented after Bakelite.

There are reinforcing fibers that automotive tire manufacturers advertise made of steel and kevlar for higher performance tires. Kevlar is plastic and IIRC was invented in the 60's.

From riding a bicycle as a hobby, most of my puncture flats on the road come from tiny steel strands that come off of tires that have been used a little too much. I imagine the steel fibers just rust away eventually but the kevlar just gets ground into tinier and tinier bits.

Yes,they're a blend of synthetics including plastics.

Didn’t I just see a post on HN that blamed ships for the plastic?

That's true for the ocean at large, this is about California's coastal areas.

Are there tires that are not made of plastic?

I dunno about no plastic but there may be less plastic tires. Maybe.

When I last bought new tires, I found out that tires lose a ton of their performance even at 50% wear rating. I thought I was doing well picking better tires than factory for my vehicles but it turns out any new tire would have had better handling because it was new.

As is common, people don't talk about the problems with their product until they have a solution. Michelin was experimenting with tire construction and formulas that were both greener and retained more of their behavior at 50% (or was that 70%?) wear level. Part of the rubber compound was derived from seed oils.

Of course, any woodworker knows about boiled linseed oil. When exposed to air it undergoes an exothermic reaction with oxygen that polymerizes it. Bioplastic. I'm not entirely sure nature makes a distinction between that substance and synthetic plastics.

So I'm a little skeptical of Michelin's woo woo about natural materials, since I'm no chemist and who knows what happens to those oils during the manufacturing process. I bought the tires but only patted myself on the back for having a safer car, not saving the planet via consumption.

There are also significant decreases in performance due to wear isn't due to the material itself, but also the change in geometry. For instance, when rain grooves wear down, they're not able to channel away as much water.

Yeah that was another of their tricks. Bury sipes into the rubber so that new ones open as the old ones wear out.

Boiled linseed oil is flax seed oil that has been processed by (heavy metals as I recall) - the chemical reaction looks like boiling which is why it is called boiled. So this finish is a synthetic plastic by definition.

Yes but they generally only get used on rails and in low speed applications.

This does not in anyway apply to Tesla right?

Teslas use regenerative brakes for 90% of braking, so brake pad dust is greatly reduced, but tire wear is no different, if not somewhat higher. It's not just the weight of the cars, but the high torque on acceleration tends to wear tires faster.

Doubly so, as they are heavier, and faster accelerating than ICE cars universally by class.

Imagine all the problems that would be solved if someone invented a car with metal wheels, maybe one that can hold hundreds of people, goes really fast, is quiet and efficient....

...and can only go to select locations at certain times that may or may not align with your final destination or schedule.

the last mile problem can be solved in a million different ways: bikes, taxis, uber, walking, buses...

Eliminating car culture is non optional if we want to save the planet.

The last mile problem can only be solved by eliminating single family detached homes. You can only reduce the amount of energy required to move bodies so much, at some point you have to start reducing the distances traveled.

The original idea of the suburbs, prior to the model-T, was for them to be small, walkable villages spread along networks of commuter rail lines.

I'd rather go with the less people travelling further on bikes route. There's a 1:1 ratio between amount of space (and therefor nature) per person, and the distance we're willing to travel on foot/bike/etc.

I rather go with less people...

bikes have tires too

and shoes are made of plastics as well

Bicycle tires are made of and release much less rubber than cars.

Funny enough, it might actually be kind of nice to work towards a world where being barefoot is okay.

Would require a lot cleaner cities. Clean bare feet could become a sign of affluence: "I'm so rich, I only walk where it's clean."

VR, then?

bikes, taxis, uber, walking, buses

Three of those four fail to address the tire issue, which is at the root of this problem.

They significantly reduce it, though, because that + trains means eliminating car traffic that is not last mile, i.e. almost all of it.

4 of 5 use traditional tires. Walking uses "plastics" as well if you're using normal shoes with rubber/"plastic" soles.

It's easy to say "use trains" when you live in a highly dense area. But America-the-continent is massive and not very dense on average. I'm not convinced trains would be viable economically like they are in Japan.

Nobody is arguing that there needs to be a subway with hourly service between Denver and Boise. There is no excuse for the coasts, south, and midwest not to have better train service. If you exclude Alaska and the Mountain States, the US has the same population density as Europe.

This is often overlooked by people with superficial understanding of American geography. Ohio has the same population density as Spain, and a higher per-capita GSP, but none of Ohio’s cities enjoys rail service of any kind.

Setting aside whether is is reasonable to judge the density of the US by only measuring dense areas, Ohio does have rail service. Amtrak serves Toledo, Cleveland, and Cincinnati. And there is heavy and light commuter rail in Cleveland.



You are on to something though, in that Columbus, the largest city in Ohio, and several of the other major cities are not served.

The major cities of Columbus, Akron and Dayton do not have Amtrak service. Columbus is the largest metropolitan area in the U.S. without passenger rail service. Columbus last had service with the National Limited in 1979. Dayton (which lost service in 1979) and Akron (which lost service in 2005) are the eleventh and twelfth.[2]

They would be if the negative externalities of autos were priced in; trains aren't viable in America because autos are subsidized via substantial non-internalized negative externalities.

That is not why trains are not viable in America.

Trains are far more heavily subsidized than autos, for example, on a per-passenger mile basis. Studies that account for the full bore of taxes which apply to personal vehicles (sales tax, excise tax, gas tax, registration fees) show that cars provide significant net income to government far exceeding infrastructure outlays.

I think that trains being less fuel efficient than cars with 2 occupants also is a good reason why “non-internalized negative externalities” have a hard time helping trains catch up in the final accounting.

If you can cite a study which supports your claim I would be very interested to read it. However, I don’t think the science of accounting for PM2.5 tire and brake dust is at the point where we can calculate the economic cost.

TIL gas taxes paid for Boston's Big Dig. What states actually reap a surplus from personal auto fees?

Meanwhile, are you including in your thought process any of the following?

- Public land permanently dedicated to roads, highways, parking lots, etc

- Parking minimums in zoning codes

- Police resources dedicated to traffic enforcement

- Wars of aggression fought to preserve oil prices

- Oil industry subsidies

- Innocent deaths and crippling lifetime injuries caused by automobiles

- Massive declining public health due to sedentary lifestyles (sitting on your butt in a driver's seat)

In order:

Public land will be permanently dedicated to rails and stations and things, if you want to cover the same area with transit access, you'll need similar, if not the same public land.

Parking minimums are not about being pro-car so much as being about anti-poor. This is a subsidy to entrenched interests, not to cars.

Police make money from traffic enforcement. Many departments get their whole budget from that. Many towns get their whole budget, above and beyond the PD, from it. Eliminate cars tomorrow and you bankrupt a huge percentage of non-major cities and all small towns.

Wars of aggression over oil are likely over due to fracking and oil sands, but I'll grant that they were bad while they were happening. Now, how are your predominantly diesel trains going to be powered without oil?

Oil subsidies are a problem. I would love to see congestion pricing and an end to all subsidies for transit, trains, buses, cars, bikes and pedestrian behaviors. We do not and never will again live in that world.

Deaths due to automobiles are at a record low per passenger mile and continuing to fall. Every time we make roads and cars and esp new cars more expensive, these rise as people limp their dangerous old clunker along a bit more. Weirdly, the requirements for safety technology cause people to drive older, less fuel efficient cars and the requirements for better emissions cause people to drive older, less safe cars all due to rising prices. Perhaps we should subsidize the removal of old cars (cash for clunkers)?

I don't think you can blame sedentary lifestyles on driving. That's a step too far -- it's a factor, but it's by no means the biggest or the most consistent. I doubt that we'd be able to attribute anywhere near enough health problem to only and specifically long commutes to even really price this externality.

1) Single occupant car transport is the least space efficient mode of travel in wide use, with wide margins. That even includes dedicated rail, if reasonably frequented, as in a moderately dense city.

2) Phrase it as you may, parking minimums raise cost of housing and/or disperse the cities increasing distances traveled, turning cheap options of walking or cycling into requisite car travel, which again widens roads, increasing distances...

3) No idea if true. Even so, less cars and less oil should leave more available resources for more useful things. Bad funding schemes are an argument, but I would consider it a sufficient one.

4) Yes they were bad. Probably still are. Trains can be electrified and no idea how that relates to wars.

5) I agree car subsidies are bad. Not sure about feasibility or seriousness of proposed end on pedestrian subsidies. Would you stop building sidewalks? Roads?

6) I will deflect to a more pressing concern and argue car travel inflicted pollution collectively does significantly more harm to health and quality of life of most residents, than the few, yet no less tragic traffic accidents.

How about we don't incentivize car usage, including all the reasons that make it convenient, useful and often almost unavoidable, like zoning, parking, wide roads, cheap fuel etc? Car is a car, and in this instance, newer cars may be even worse polluters with their tire particulate.

7) Sedentary life style is not about length of commute. If you don't own a powered personal transporter, you will almost certainly either walk more or cycle more or at least stand on your motorized scooter as you do want to get somewhere.

Don't forget about the huge amount of spending on hospitals and morgues required for the 40,000 dead every single year (more than guns shots), and 2.35 million that are injured or disabled.

$38 billion a year in sales taxes from new and used automobiles and services.

$66 billion a year in use taxes including fuel, excise, and registration.

That’s just the direct revenue. If you want to include externalities, you also have to include economic activity enabled by these investments, and the taxes on those activities.

Just the auto sector alone produces $60 billion of income tax revenue for state and Federal governments.

But that’s not even scratching the surface of total economic activity supported by the national highway infrastructure, or state and local infrastructure, which arguably holds up double digits percentages of GDP. State income taxes rise and fall based on their infrastructure investments.

Even the Big Dig (at $14 billion in cost I assume due to massive fraud) eventually not only pays for itself but is massively profitable from a combination of vehicle cost savings and in future revenue streams from increased economic activity enabled by the new infrastructure and added prime real estate. [1]

A lot of people die or are injured on the highways. Did you also attempt to measure the lives bettered and saved because of those same highways?

An informed discussion balances positives and negatives of any activity, along with the positives and negatives of a proposed substitute.

There’s a reason why infrastructure spending is one of the very few things which garners almost universal support from all political parties.

[1] - https://www.edrgroup.com/library/highways/economic-impact-ce...

Road crashes cost the U.S. $230.6 billion per year, or an average of $820 per person.


Actually it’s much worse than that. $277 billion is the economic cost of car accidents. The cost including lost wages and human suffering is estimated at $871 billion per year. [1]

There’s a difference between direct revenue & expenses and second-order effects.

As a second order effect, roads are necessary for something on the order of $10 trillion of economic activity in the US.

It’s a high price to pay to be sure, for the modern world. I look forward to self driving technology significantly reducing that number over the next 10-15 years.

[1] - https://www.pbs.org/newshour/nation/motor-vehicle-crashes-u-...

> Studies that account for the full bore of taxes which apply to personal vehicles (sales tax, excise tax, gas tax, registration fees) show that cars provide significant net income to government far exceeding infrastructure outlays.

I'm not talking infrastructure externalities, I'm talking about environmental externalities, especially (but not exclusively) tailpipe emissions.

>I'm not convinced trains would be viable economically like they are in Japan.

In my opinion I think rail would displace a great deal of airline traffic because air travel security is such a chore, airlines have done their very best to squeeze out every last nickel and concerns about how green air travel is or is not. Add in the fact that there is far more room per passenger in a train and with dining cars (which are slowly dying) the food can be much better.

The biggest downside to rail travel in the US is the rail lines are owned by and geared for freight train operators. You really need completely separate lines (as you have in Japan) to compete on speed, but then competing on price would be difficult since it means building entirely new infrastructure. It could require government subsidy and in the current political climate that seems unlikely.

Current technologies are too far behind in speed though. Passengers will trade better wifi, food, space, etc, in exchange for longer travel times but only up to a point. If a New York to LA trip goes from 5 to 25 hours then it's no longer viable. Unfortunately the radius that trains can be competitive barely reaches from LA to SF.

>Current technologies are too far behind in speed though.

That depends entirely on the distance traveled; no one is suggesting a replacement of transcontinental flights with trains. But there's plenty of medium and short haul flights (for example) that would be far more comfortable on a train with little difference in total travel time once you've factored airport security overhead.

I'll give you a practical example: my wife and I live in Houston and regularly visit New Orleans. It's a one hour and five minute flight on Southwest which is one of the few airlines that still allow two suitcases per passenger for free. That's a five to six hour drive if I choose to go by car and with rare exception I choose to drive. I'm happy to trade two to three more hours on the road versus the hassle of dealing with the airport.

>Passengers will trade better wifi, food, space, etc, in exchange for longer travel times but only up to a point.

The time to travel between Houston to New Orleans would be two to three hours by high speed train. That's competitive with the Southwest flight and fast enough I'd seriously consider versus driving myself. In fact at those speeds I'd start looking at longer trips either to Mexico, farther West to Arizona, New Mexico or Colorado or farther East to tourist destinations there. At least for me it would increase my travel options and I'd be sure to take advantage over it over flying.

Sure, but then I'll point to my other comments that politically and economically this isn't viable.

Adding a train line requires an immense real-estate investment, likely with lots of battles with existing land owners who don't want to sell. After that, you're stuck with that route whether it makes money or not, and how many riders really travel between those cities in the first place?

This is the problem with CA's high speed rail line. They ended up placing both ends in the middle of nowhere when even the LA->SF route would have barely gotten the ridership needed to work.

Planes can reroute all the time and independently control schedules and payloads to account for actual passenger demand, while also only needing an airport on either end which already exist.

If a train was built, you'd be paying 10x more for a ticket than the airline. Is that something you would do? Something many others would do?

Anti rail sentiment has been with us since the advent of rail itself and really the arguments haven't changed.


The same arguments against rail can be made (for example) against new roads and exactly for the same reasons: they just go one place, you have to fight land owners to put them in and what if no one uses them?

Sure, but then I'll point to my other comments that politically and economically this isn't viable.

Adding a train line requires an immense real-estate investment, likely with lots of battles with existing land owners who don't want to sell. After that, you're stuck with that route whether it makes money or not, and how many riders really travel between those cities in the first place?

Planes can reroute all the time and independently control schedules and payloads to account for actual passenger demand, while also only needing an airport on either end which already exist.

If a train was built, you'd be paying 10x more for a ticket than the airline. Is that something you would do? Something many others would do? Just to get there at basically the same time in the end?

This is such a tired argument and reflects your superficial comprehension of this topic. Yes, NY to LA is too far for rail service. It is the same distance from Paris to Moscow. Nobody takes trains between Paris and Moscow. However the territory between Paris and Moscow, including both Paris and Moscow, enjoy very robust rail service. The fact that the USA happens to be a large and unified political jurisdiction in no way detracts from the fact that we have local and regional opportunities to establish passenger rail networks.

Since you have a new account, I'll vouch for your comment to keep it alive, but please get rid of that disparaging attitude on HN.

If you're going within a city, then home->dest time is roughly equal to home->station->train->station->dest, so if you're going to use a car anyway then you might as well just drive all the way, with more comfort, privacy, and convenience. Stations within walking distance are not realistic except in very dense urban areas like NY (which already has subways).

If you're going between cities, traffic is actually not much of an issue so it's again the same equation. Once distance increases to the point of a train being faster (even with stops), air travel then starts to become a better option.

Rail requires density. American cities are very spread out and internally sparse internally. Last mile is a serious problem, and that's before considering politics, real-estate, security and defense issues, pricing models, taxes, and other factors. Meanwhile roads are cheap and give people ultimate flexibility.

We would all love better transport, but pretending it's simple just because some other country somewhere has some trains isn't very useful.

but at least half of the country lives in a dense area. surely it'd be a start to remove the need for cars in cities > 200,000 people.

82% of the US population lives in urban areas. Most Americans look out their front door to see a dense metropolis with thousands of people per square mile.

The upshot of this is that quite a modest train network could easily serve 50%+ of Americans. Once that's done, then you can come back and complain about how it's hard to run trains to that one guy who lives in a shack somewhere, and I'll agree with you.

Think of it like the interstate highway system. Yes, not every single American has a highway running to their door. But a heck of lot of people make daily use of the system and 100% of the population benefits from it.

I don't expect trains or rail to take over every middle-sized town, but the 1-2 million+ cities should all be (and many are) looking at revitalizing downtown areas for greater density and walkability. And it would be great for tightly connected metro areas to have high speed rail between them.

You don't even need to go that far. Eliminating car culture is how you'd make a city I'd actually enjoy living in.

Non optional says whom? I'm rather excited about the new Tesla batteries and the possibilities of traveling more for less money per mile. You can live in relative poverty compared to today and ride a bike and only travel in a highly ordered and grating manner, but I'll support nuclear power and have fun around town in a 750hp electric.

Unless you live more than a mile away... Lots of people don't live in densely populated areas near train tracks where getting off the train and getting home is <10 minutes.

Obviously, it makes sense for those who do but most of America is sprawly and isn't designed for rail transit efficiency.

I'd appreciate good quite rail but it isn't anywhere near feasible in these sprawly landscapes.

> Lots of people don't live in densely populated areas

but MOST of the people do live (or around) densely populated areas, no? (just checked - google says 82% of US population is in urban areas). Addressing issues for most of the people first would have the most impact.

I will repeat a comment that I have made on HN before:

50% of the US population live in just 35 metropolitan areas (Los Angeles, CA; New York, NY; Chicago, IL; Philadelphia, PA; Washington, DC; Detroit, MI; Houston, TX; Atlanta, GA; Dallas, TX; Boston, MA; San Bernardino, CA; Phoenix, AZ; Minneapolis, MN; Orange County, CA; San Diego, CA; Nassau, NY; St. Louis, IL; Baltimore, MD; Seattle, WA; Tampa, FL; Oakland, CA; Pittsburgh, PA; Miami, FL; Cleveland, OH; Denver, CO; Newark, NJ; Portland, OR; Kansas City, MO; San Francisco, CA; Fort Worth, TX; San Jose, CA; Cincinnati, OH; Orlando, FL; Sacramento, CA; Fort Lauderdale, FL) that together have 173328 square miles. That is a density of 654 inhabitants per square mile or 253 inhabitants per square kilometer. Compare that with the 232 inhabitants per square kilometer in Germany, or the 118 inhabitants per square kilometer in France. And yes you can live without a car even in rural Germany (at least if you don't have kids).

The 20 densest metropolitan areas contain 25% of the US population and have 400 inhabitants per square kilometer, comparable to the 416 inhabitants per square kilometer averaged over the Netherlands.

The lack of public transport in the US is not a density problem. That is just the excuse because people don't want to change.

And before anybody says "but the density in German cities is much higher": I lived for years in a German district with a density of 217 inhabitants per square kilometer, without needing a car.

"Without needing a car" is pretty vague. There are many people in the USA who live all over who don't own a car.

I lived in a small town of 4,500 people without a car too. Same for a 20,000 person one. Same for a 160,000 one. Same for a 600,000+. I've done it in multiple 1+ million cities too.

It doesn't mean your quality of life is the same as it would be with a car.

Regardless - I don't think comparing Germany to the USA with population density is going to work. A lot of Germany is clustered with high density. You can put a million people in 1 square mile, leave 999 square miles empty and it'll have the same population density as any other 1000 square mile 1000/mi region.

Sprawl is the issue with the USA. That 600 habits per square mile goes out forever whereas in Germany it has a tendency to fall off exponentially.

If you go to places like Norway then you'll notice they won't even let people build outside their city proper. Once you get outside Oslo, it turns completely green and there's just road and rail. Almost no houses until you get to small dense towns. In comparison to the USA where the houses go on and on and on and on and on and on. The lots just get bigger and bigger whereas the homes in these other countries tend to stay the same size and so does the property.

You can separate the issue better by saying intercity and intracity. Getting from your home to a location is usually not much more time than getting from your home to a station. This makes trains unviable for most inner-city travel outside of some lightrail in dense urban areas.

For intercity, trains quickly start competing against airlines which are better for most domestic travel because the US is so big.

Have you lived in a city with a subway? Give it a few years, and all the stuff is nearer the trains stops anyways. The train is rarely out of the way.

I currently live in both New York and Los Angeles. The subways in NY work because of density, but they won't work in LA. Lightrail can be improved, and more lines added, but you're not going to get NY mobility in LA with trains alone. Not until someone solves the last-mile reach with something other than cars.

Transportation determines density.

Maybe when it was all empty land. Right now the current density is what determines what transportation is viable, or can even be built. Even acquiring the land would be incredibly difficult with our politics and economics.

Subways are one of the most effective inner-city travel systems available. I'd consider that a train system.

I'm always reminded of this when I visit Toronto— the last time I was there, my partner and I were going to see a small concert in the west end, and I groaned as Google Maps told me it would be a 40 minute trip by TTC, including the walk at both ends.

Usually we would have taken the subway, but for whatever reason I was feeling lazy this time so we drove. It was almost a half-hour trip across downtown through the tail end of rush hour, and then ten minutes of circling the block looking at parking lots and garages that were already full, and then another ten minutes of walking back to the venue from the street parking we finally found several blocks away.

And no, the solution is not "build more parking", the solution is to further incentivise mass transit use. For example, in this case, I probably would have been dissuaded from driving if Google Maps had not only incorporate traffic delays into its estimate, but also highlighted that the apparently plentiful nearby parking lots were all likely to be full at the time of my planned arrival.

If you remove the parking situation from large-scale events, then the travel time is the same if not faster with the car, while providing more freedom and comfort. That's why many people choose it.

Unless you within walking distance of a station, you're going to get in a car anyway and at that point it's usually faster and cheap to drive. That's the fundamental calculus that prevents large-scale train construction in CA cities.

But changing the parking situation changes everything. The concert we went to was an The Great Hall on Queen St W. There were only a few hundred people at the event, but nowhere around there were there a few hundred parking spots— the whole neighbourhood is packed with restaurants, clubs, and other destinations. The character of it would be completely changed by setting all that stuff up to be accessed primarily by personal vehicle.

The reality is, most of the people around us attending the event got there by some combination of transit, walking, and uber/cabs. And we should have too; we'll know for next time.

Like I said, it depends on density. If the home-to-station time is short enough then it already exists (like in New York) but in other places it's faster to just drive to the location rather than to/from a station on both ends (like in Los Angeles).

Density and last mile is the critical factor. Most cities in the US are too spread out currently.

all but one of those have wheels that would shed the same microplastics.

> Eliminating car culture is non optional if we want to save the planet.

That could work, or you know, we could continue research and development of tires with better PM2.5 ratings and vehicles that run on sustainable energy.

I wonder which could be done without a multi-trillion dollar hit on the global economy?

I mean cars have the same problems right? Or have traffic jams, road closures, and parking restrictions by time of day gone away?

Similar, but not exactly the same. My car goes when I want to go. The train goes when it goes even when I'm not there. I ride the bus to work, I am often annoyed to arrive at work 20 minutes early when I really wanted to sleep in those 20 minutes, but the bus runs on a half hour schedule - too bad for my preference. Traffic jams, road closures and parking restrictions are an issue for some, but I'm lucky enough that for the places I go they are not (between living in a small town and alternate routes I can get around by car with no problems).

I take the bus, I'm trading a bit of time for the convenience of having someone else drive, and a forced exercise program walking to the bus stop. Several times a month I need to go someplace where the bus doesn't go without an unreasonably long walk.

Imagine someone invented some form of city planning that does not require people to use cars.

They did, unfortunately no one remembered to bring it over from Europe.

That did exist in the US Northeast when I was a kid. Most everything we needed could be walked to. Walmart, Home Depot, and other chains eventually killed off all the walking distance mom and pop restaurants, grocery marts and shops.

This is happening in my hometown Chitré, Panama, an 80k population town in a developing country. But ask almost anyone and they'll tell you how Chitré feels more and more like the capital city, i.e. more developed. No politician in her right mind is going to propose increasing tariffs on cars and taxes on fuel. People thinks its perfectly OK if pedestrians have access to the worst infrastructure, while cars proliferate. After all, you work hard, buy a car, close the windows, turn on the AC, and let the underachievers breathe burned fuel. The world is in order.

Update: I've also stayed several months in Chile, which based on GDP, HDI, and Gini Coefficient, is a more developed country. Fuel is twice the price as in Panama, pedestrian infrastructure is well maintained, and the car driver culture in terms of following rules is the opposite of Panama. Mom and pop shops are the norm there, everywhere I went.

I don’t know about the “quiet and efficient” but the rest of that describes a large armored personnel carrier: https://en.wikipedia.org/wiki/Armored_personnel_carrier

The Michelin airless tire is getting close.. (still uses rubber but not nearly as much as conventional tires)


It uses the same amount of rubber on the part that matters for the subject. The microplastics in this case are not caused by the total rubber content, but the rubber that is lost through road wear, and that will be the same on the airless tires, as it cannot be changed without impacting the grip (or the cars will have the same problems as the trains discussed above - huge stopping distance, unable to go up a >2% slope without special tricks).

They've been working on this for decades already, with the Tweel getting some attention in 2005: https://en.wikipedia.org/wiki/Tweel

It'll be a long time still before this actually gets to any kind of production use, unless regulation steps in.

I'm not sure how this helps. The amount of rubber used is not as important as the surface area being deteriorated, which doesn't seem to be any different from conventional tires.

just made me think the efficiency depends upon the utilization, so it's high when many ride and low when not.

But it doesn't take many mass transit riders to make that vehicle more efficient than a single-occupancy car.


"quiet and efficient" definitely does not exist in California currently

Trains are less efficient than cars on a per mile basis.


That study seems to only look at Amtrak trains, so it doesn't consider the large number of subway or urban light rail systems in use. Amtrak has relatively few passengers (along with many other problems). The NYC subway system, for example, is far, far more fuel efficient than a car. As is probably any moderately used metro service.

The article says underutilised, old and inefficient US Antrak trains are less efficient. Thsts quite believable, but isn't a general comment against trains.

From the article: "In the US: Cars are generally more efficient than trains when there are 2 or more people traveling."

That's rare. The vast majority of traffic is 1 person per car, which completely changes the results here to make it worse than the rest.

The blended 2017 US average is 1.54 people per car, source: https://www.energy.gov/eere/vehicles/articles/fotw-1040-july...

Sounds like trains are less efficient than cars maybe only in the US, because of lots of empty seats and/or less cars per passenger train:

>In the fuel efficiency information provided below you’ll see that trains are unexpectedly low, but this data can be a bit misleading because it’s from research that only studied trains in the US. There are two things to note:

>1) Americans don’t utilize trains as a mode of transportation very much in comparison with European and Asian countries. This brings fuel efficiency down because there are less people being transported per train moving.

>2)Trains have varying fuel efficiencies themselves. They are powered by either a normal combustion engine using diesel fuel or an electric motor. The efficiency of electric trains is highly variable because of the source of electricity. Electricity from a coal fired power plant will be much less efficient then renewable resources such as hydroelectric, wind, or solar.

Normalization on a per-mile basis misses the point. You build dense, transit-oriented cities specifically to reduce that denominator. Moving a person one mile has no intrinsic value whatsoever.

When you measure comfort per mile, cars are nearly infinitely superior to trains.

I don't know about that. I've been on some nice trains and I've been in some crappy cars.

You've done it. You've figured it out. Nobody else has. Amazing.

The effectiveness of trains is directly related to the distance between stops, and California (and much of the USA) is too spread out for current combination of technologies and politics.

Large swaths of suburbia must be abandoned and the remaining hubs densified to fix this. No exaggeration.

We're doing a fine job of emptying the rural areas, heh, so I see no reason this isn't possible.

On the front page of HN at the exact same time, we have two different articles on this topic. One says that most ocean plastic comes from ships, the other says car tires. Clearly they're both accurate.

Of course they can both be accurate. There's a difference between California's coastal waters and the ocean in general.

.. the other says <micro>plastics in California coastal waters. Sounds similar, but not the same thing and they can both be accurate at the same time.

Once is in CA coastal waters, the other one is in oceans. They can both be right.

One is measuring number of particles, and the other total amount of plastic.

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