Tire rubber shedding has been much reduced as tire life has increased. Look at old highway pictures from the 1950s and 1960s. You can often see tire tracks on paved roads. Plus, of course, the industry standard oil leak in the center of the lane.
Why would tires contain cadmium or lead?
Here's a good tire recycling plant.[1] The process is straightforward. Chop up the tires, re-chop to smaller pieces, magnetically separate metal tire cords, grind up remaining rubber component, ship rubber to plant that makes rubber products, ship steel to steel mill.
Many videos of tire recycling plants on Youtube show inefficient operations. Big piles of partially chopped up tires, no reduction to a usable powder, no metal separation, not enough throughput. Serious operations have a front-end loader putting tires into the input hopper. Ones that look like subsidized demo plants have someone putting one tire at a time onto a conveyor. (They also tend to have names involving "Eco" and "Green". The serious players talk about tons per hour and the value of the product that comes out.)
(a random article warning about heavy metal contamination of rubber stoppers used in drug manufacturing).
I remember 1493 talking about how natural rubber, while it has many otherwise useful properties, responds poorly to heat and cold. So vulcanization and other chemical transformations helped improve that and make rubber appropriate for a much wider range of applications. It looks like some of the vulcanization processes use metal oxides, including lead oxides, as an additive. The examples on the Wikipedia page using lead oxides are for neoprene (which is unlikely to be in tires, I guess) but it seems that butadiene, which is in tires, is made with "metal oxide catalysts"
I wonder if the catalysts contaminate the resulting product or something. (Clearly the butadiene itself isn't supposed to contain metals and the catalyst, being a catalyst, isn't supposed to be absorbed into the reaction.)
Could there be rubber manufacturers who just throw some heavy metal oxides directly into their rubber because they're cheap and they help make the end product more durable, even though there are in principle better and safer ways to achieve the same results? Maybe they're thinking "this particular rubber isn't going to be eaten or come in contact with food, and it's not going to come in contact with skin very much, so it doesn't really matter if it's a bit toxic". I've seen Prop 65 warnings for lead on all sorts of electrical cables -- maybe it was used to manufacture the rubbers and vinyls in the insulators?
What nobody talks about is the link between this rubber pollution and safety. Modern cars have huge oversized tires with massive friction potentials. In normal driving we never get anywhere near those friction limits. It all sits in reserve for that time we need to stop now. Our cars can stop on a dime in an emergency, far far shorter than current regulations mandate. Compare any new car today to a classic car from the 60s or 70s (on the old rubber). Our stopping distances today are half or even a third of previously accepted norms. The price for that ability: rubber on the road. It is a choice we have actively made, one i doubt many would reconsider. Who here would buy a non-polluting tire if it meant your car stopped even 25% slower?
I always thought BEVs would be way heavier and I remember looking my model 3 up before I bought it and was surprised. Did a quick look again and here are the curb weights I found.
Tesla Model 3: 3,686lbs
Audi A4 2020: 3417-3627
2020 BMW 3-Series: 3582
Ya, they are all similar performance/luxury sedans. Compart the Honda Civic, a pretty standard car, with a curb weight of 2770lbs. A thousand pounds less.
Judging by the absence of regular safety inspections in vast parts of the US... mostly no one cares? Talk about an active choice there.
The stopping distance fetish is weird in any case, whatever benefit you got from stopping faster is obviated by the outsized inflation in vehicle weights.
I've lived in states with and without mandatory safety inspections. If I remember right, the statistical evidence shows that accidents involving mechanical issues are the same between states that require an inspection and those which don't. The vast majority of accidents are driver error. And in my opinion, most of those are because the driver's test is a joke.
"The stopping distance fetish is weird in any case, whatever benefit you got from stopping faster is obviated by the outsized inflation in vehicle weights."
I'm not sure what you mean by this. I have actually weighed vehicles in the past and the weight was very close to the specs. If we are talking about sports cars (where the majority of spec discussions occur), then I would gladly see people talking about stopping distance opposed/in addition to the horsepower "fetish" - you have to be able to stop those ponies.
Stopping distance won't seem like a ''fetish'' to some kid who cases his ball onto a busy street and doesn't get his brains splattered because cars do stop faster than they once did.
Had this type of thing happen twice, in both an old an new car.
New car (stops 60-0 in 101'): Doing 30mph. Middle school kid just didn't look and stepped into the road about 35' in front of me. I slammed the clutch and brake and the deceleration was very rapid. No contact or injuries - plenty of room. Not sure how he didn't hear the loud(ish) car coming up the hill prior to that.
Old car (60-0 in 120' when new, more likely much longer at this point): Doing about 35 mph. High school kid wearing earbuds decides to step out without looking about 20' in front of me. I feather the pedal and it wasn't looking good. At least the kid heard the right front lock-up an got back on the side of the road. If he were walking on the correct side of the road, this wouldn't have been an issue since you can see the oncoming traffic close to you (no sidewalk).
What is it with people not looking before crossing the street? They teach this in pre-K/Kindergarden.
Yes children should be taught about road safety but they’re not the ones operating a two ton high speed machine. Pools are fenced because those owning hazards have a duty to safeguard children from them. Children don’t have a duty to be as responsible as an adult would be.
So, fence the roadways and only allow crosswalks that electronically control a gate to allow pedestrians to cross when traffic is stopped? We already have laws in place to protect pedestrians, including children. Children are still required to follow the law and are expected to know right from wrong at a young age (mens rea around age 8 depending on state). So they are expected, by law, to be as responsible as an adult.
Your fence analogy is flawed. The fence is a requirement by law, just as crosswalks and their use are required by law. Neither kid was using a crosswalk or even gave any indication they were going to cross the street (such as turning to look at traffic). They simply stepped into traffic without looking. There's no legal basis for a driver to be held responsible in the scenarios I described where the driver is operating lawfully (attentive, at or under the speed limit, etc) and the pedestrian decides to step out without any indication and in violation of the law. The driver in that scenario performed all their lawful duties but even a lawful driver is not likely to be able to stop a car that takes 30-40 feet to stop at 35mph when someone steps out at 20 feet. Just as someone with a fence around their pool would have fulfilled their lawful duties if a high school kid tresspassed by jumping that fence and drowned.
Parents have a duty to safeguard their children. If you allow your child to go unsupervised, then you could be found responsible their actions if they do something wrong (parent's negligence in not supervising a minor). Some states or cities even make it a crime to allow a child under a specific age to go unsupervised whether they did something wrong or not (curfews are very common). But it is generally up to the parent to decide if their child can safely perform an action such as walking along a street or staying home alone.
I'd hardly call 30-35 mph high speed, unless we're calling bicycles high speed too. Typically when talking about cars, high speed would be considered at least highway speeds in excess of 50mph.
It's nice you are concerned for the kids, now you just need to collectively remember it when it comes to buying trucks & SUVs that have the grille on head height, sight angles that make it impossible to see small kids just walking in front of you on a crosswalk and with their height rob kids of the ability to see anything but a wall of metal around them.
If only crosswalks were the only places children might approach a street, stopping distance might not be so relevant. And you need to remember that not all vehicles are SUVs or pickup trucks, even in America, and regular small cars benefit from larger tires as well.
No matter how small your car, and no matter how perfect your attention to your surroundings, larger tires are safer.
I have experience in tuning race cars of different kinds and I can tell you that bigger tires are not always better.
Light car with big tires is veeeery sketchy to drive in rain. I had a Miata with 225 wide super sticky tires and I couldn’t go over 60 on the highway without being very nervous. I went down to 205s and it’s way more street friendly.
Roads with some gravel, dirt, or otherwise not so perfect are also not great with too big of a tire because the car rolls on the little pebbles or rocks instead of shaping itself around it. The pounds per inch go down enough that the tire won’t get pushed around the rock to contact the asphalt.
There is a “safe for the average guy” tire width and a “experienced enthusiast that wants some extra Gs in the turns” width.
Can confirm - hyroplaning is much more common in wider tires assuming the same vehicle weight. 285s are awesome on dry roads, but not so friendly in a downpour. Was definitely made fun of pretty hard by my non-car-guy friends for my slow driving that day.
I drive a truck and have no problem seeing small children approaching and crossing a crosswalk. I really don't see how your comment attacking trucks and SUV has any impact on their safety when it comes to seeing pedestrians, or pedestrians' visibility (if anything, they'd be more likely to see you).
It seems like the obvious solution is lower speed limits and less deadly cars. Not more pollution in case the person texting on their phone at 30+mph looks up from their phone a split second before they notice a kid playing in or crossing the street.
That's a fine snarky retort if you only consider idealised abstract scenarios. In the real world, streets are lined with all manner of visual obstructions that children, deer, etc may be hidden by. Bushes, cars, buildings or garden walls; any speed above parking lot speeds has the potential to kill somebody or something in real world scenarios. Shit happens.
I wasn’t being snarky, and I’m well aware of real world scenarios. I’ve biked in NYC for over a decade, I’ve worked in transportation and volunteer my time for building safer streets. The majority of drivers I see on the street at looking at phones on their laps, or dashboards where their phone is hanging.
The obstacles you named(visual obstructions) are all also things that should not exist as much as they do in their current forms. Daylighting intersections to improve sight lines, smaller cars to prevent crushing kids and also improve sight lines, narrower streets to reduce speeds are not idealized abstract scenarios. Plenty of countries outside of the USA have this as a reality and a few have achieved 0 traffic deaths, and that is owed almost entirely to street design, not bigger car tires.
‘Shit Happens’, yes. But there are significantly better ways to make ‘shit happen’ less, and make it less deadly for the people outside of a car.
Saying that visual obstructions should not exist is fine if we're all being idealists daydreaming about the changes we would impose when we become Emperors of the world. But in the meantime, stopping distance is important.
Making the changes you propose in urban settings wouldn't even be sufficient. Or do you also mean to clearcut all forests within 50 meters of all roads, then nuke the grass with herbicides? A year ago when driving Alaska Highway 5 during dusk I was nearly killed by a moose. The trees there were cut away from the roads, but the grass was high enough to hide the moose until I was almost next to it. And about ten years ago in Pennsylvania, I did hit a deer in similar circumstances. Thankfully I was able to slow down enough that it didn't come through my windshield. There is no way in hell I would ever opt for any system that increases my stopping distance. ABS and good tires are no longer optional as far as I'm personally concerned.
My initial comment said that, but was edited 30 minutes prior to your reply to include ‘as much as they do in their current forms’ to make my point clearer. I’m not sure if you had the old message cached, but I’d recommend re-reading the point I was making. I don’t believe we disagree with each other. Stopping distance does matter, but there are solutions that exist that are cheaper, more effective, and less destructive. It unfortunately feels like you’re the one being snarky though by comparing street-level solutions like daylighting intersections to idealistic daydreaming and something only fit for an ‘Emperor of the world’ to take on. In reality, those changes typically come up during community meetings and DOT planning sessions. Hardly emperor-level discussions, and input is typically open to the public.
No thanks. The point of cars is fast travel times and I - and I suspect much of society - would not want to see 25 mph speed limits increasing our travel times and stealing from our precious free time. It’s a tradeoff and I don’t think we have a bad balance with higher speed limits.
Planes also promise fast travel times, but if a plane crashes, we heavily investigate the cause and figure out a solution so it doesn’t occur again. The USA experiences the equivalent of over 100 Boeing 747 plane crashes a year(and rising), counting only deaths due to traffic crashes.
The number spikes significantly higher when you factor in people with severe injuries who will never fully recover(think: losing arms, legs, brain damage,etc..).
Assuming speed limits stay the same, but deaths and injuries continue to rise, at what point would you say we have a ‘bad balance’ and should adjust? What is your ‘balance’ based on? Is there some ratio of VMT(vehicle miles traveled) to occurrences of deaths and dismemberment that you keep in mind?
Speed is not the real issue. You can see that many high-speed roads have reasonable fatality rates (autoban vs. US interstates). Also, speed limits on highways in the US have been rising in recent years, mostly due to enhanced specs and safety of vehicles. Fatalities have also be declining during that time as well.
In my opinion, the real difference if the intelligence of the driver when it comes to laws, vehicle dynamics, and decision making. The US driver's test is a joke. You can see that other countries (think EU members) have tougher tests and fewer fatalities per mile, while in some cases also having higher speed limits.
Of course speed is not the only issue but it is definitely a contributing factor. One need only look at crashmapper.org to see how often ‘unsafe speed’ is a contributing factor in the couple hundred thousand reported crashes that happen annually in NYC alone.
Driver knowledge(and vision, and reaction time) is extremely important, and I completely agree that the USA is too lax in regards to licensing — One need only look at Georgia, where they ‘paused’ the need to pass a road test to be licensed[0].
But again, that’s only one piece to the puzzle. What we need is simply a change in how much a driver should be responsible for, as it’s clear that we can’t expect drivers to react in time to prevent crashes, and the shortest stopping distance in the world still wouldn’t make much of a difference in most serious crashes.
In many cities in the Netherlands and Sweden for example, they’ve mostly addressed the ‘people problem’ by designing roads to minimize conflicts between different modes of transport by default. On the other hand, in places like NYC, The DOT designs bike lanes with ‘mixing zones’ as the defacto standard. It goes completely against the primary idea of ‘Vision Zero’, which is understanding that humans make mistakes, and designing infrastructure to reduce the likelihood that mistake kills or injures someone.
That unsafe speed comment is exactly what I'm talking about. The driver made a bad decision to exceed a safe speed (usually above the speed limit that they when doing the road safety study).
It would be great to incorporate safe design aspects, although vision zero doesn't seem to be working well so far in NYC and they are even suggesting more education for cyclists in the form of licenses. But even just the increased drivers test requirements could cut fatalities by about half.
It may be a necessary precursor, or even contributing factor, in accidents but it doesn't explain the difference in fatalities per million miles between countries with strict tests and lenient tests. Thus, suggesting that another variable is at play when determining the cause (not precursor) of the accident.
But if speed is the issue and you are insinuating that a speed of 0 solves the issue, then how do you propose we move from one point of space to another? You have injuries and fatalities with other modes of transportation as well.
They already do extensive road safety studies for speed limits, lights, signs, etc. I believe fatal accidents are required by law to be extensively investigated. The less serious ones usually receive some investigation (they want to cite someone). Most of the time accidents are caused by driver error, such as inattention, not knowing the law, or simply making bad decisions. The laws and road design are usually sufficient if the driver is doing their duties correctly and responsibly.
> The laws and road design are usually sufficient if the driver is doing their duties correctly and responsibly.
Here is where the problem lay! Expecting drivers to always be attentive, lest they kill someone(or multiple people) is not a sane way to reduce traffic fatalities and injuries. You stated it yourself that driver inattention / error is a contributing factor in most crashes. In NYC, driver inattention / distraction and 'Failure to yield right of way' are the two largest leading causes of pedestrian and cyclist injuries and fatalities[0].
Sure, better education can reduce the likelihood a crash happens, but it does not reduce the severity of a crash when it happens. Reducing the severity of crashes means designing infrastructure that keeps the most vulnerable road users safe.
> I believe fatal accidents are required by law to be extensively investigated
I can't speak for most places in the USA, but in NYC this is entirely false. There are many instances of NYPD showing up to fatal crashes, asking the driver(who just ran someone over) what happened, and then just taking their word for it. It usually takes a team of lawyers at the behest of the family of the deceased to actually gather evidence[1][2]. A councilmember in NYC recently proposed a bill to get NYPD out of crash investigations for this very reason[3]
Sounds like NYC is just lazy, similar to how Philly cops wont even show up to an accident unless someone is hurt. Many states have fatal crash units that are part of the state police, for example NJ. I would guess that NY does too, but that NYC uses NYPD instead of the troopers.
Reducing the accidents is the goal. There are safety studies done prior to installing new infrastructure or when deemed necessary due to accidents. There are already things like bike lanes, crosswalks, plastic bumpers, etc to keep people safe. Education and testing is the best solution as it would provide a reduction of fatalities not just in the cities, but also on the highways. You can see that the fatality rate is about double compared to countries that have stricter tests.
Deaths and injuries don’t “continue” to rise. They’ve been falling dramatically since the 80s. They’ll continue to do so because of safety technologies like rear cameras, blind spot monitoring, lane departure detection, etc.
My balance is based on my personal values and risk assessment. I don’t fear injuries or death when I get on the road. Nor do I fear it when walking or on my bicycle. Overall the system is pretty safe and I like my modern conveniences. My point is simply to say that perfect safety isn’t a realistic or desirable goal since the returns for the risks are high.
I’m not sure why you put “continue” in quotes when my comment never included the word continue. You are correct that deaths for motor vehicle occupants are going down due to safety features specifically designed to keep the occupants safe. But car related deaths for people outside of cars is trending up and is getting grimly close to double what it was just a little over 10 years ago[0][1]
>Planes also promise fast travel times, but if a plane crashes, we heavily investigate the cause and figure out a solution so it doesn’t occur again. The USA experiences the equivalent of over 100 Boeing 747 plane crashes a year(and rising), counting only deaths due to traffic crashes. The number spikes significantly higher when you factor in people with severe injuries who will never fully recover(think: losing arms, legs, brain damage,etc..).
>Assuming speed limits stay the same, but deaths and injuries _continue_ to rise, at what point would you say we have a ‘bad balance’ and should adjust? What is your ‘balance’ based on? Is there some ratio of VMT(vehicle miles traveled) to occurrences of deaths and dismemberment that you keep in mind?
Apologies! I gave a hypothetical scenario as part of a question, that also unfortunately happened to be true when accounting for occupants outside of vehicles. I didn’t mean for you(or the OP) to interpret the scenario as me stating it as a matter of fact and quote it in a rebuttal. I’ll try and make hypotheticals like that a bit clearer in the future to avoid confusing people.
Considering how long wearing economy tires fly off the shelves compared to "nice" tires that easily have 10-20% more traction I think that society has made its preferences quite clear.
What I want to know is how many of the people in these comments talking about unconscionable even an extra millimeter of stopping distance is are actually putting their money where their mouth is and buying season specific tires.
I agree that the overall trend has been towards higher treadwear tires. One thing to note is that the treadwear of these modern tires is higher while still providing better stopping distance when compared to the old '50-'60s tires mentioned. Of course there are other factors such as anti-lock brakes, tread design, and other vehicle traits that can decrease the distance. Still, the material component does provide longer life and better performance than in the past.
Also, I have owned high performance 200 treadwear tires. The millimeters you are talking about can be meters at highway speeds. You are looking at a return in safety that increases substantially with speed. Roughly, your stopping distance quadruples when you double speed. So 30 feet at 30 mph turns into 120 feet at 60 mph (depending on a ton of factors, including tires). So some people who drive at highway speeds such as 80 mph may prefer the extra safety of performance tires which could shorten their stopping distances by 20 feet.
I've experienced enough events that having all the grip saved my life so, I wouldn't even consider it.
Traffic is a place where everyone is going with ~1 ton boxes and nobody (incl. me) is not knowing what they're doing so, every mm of safety is preferable.
Even leaving ABS and other advancements out of it, the newer compounds provide both better performance and better treadwear - so both safety and economy/environmental concerns are improved compared to the old days.
To be clear, the commenter I’m replying to edited his comment, making mine look odd.
Previously it commented on braking distances falling 40-50% between the 70s and now, and didn’t seem to be taking ABS into account
I wouldn’t even consider it. I intentionally run tires larger larger than OEM for safety. If everyone I love is in my car and there is anything I can to help protect them I will.
This is one area where I’ll proudly admit I come before mother nature. As George Carlin famously said the planet will be here long after I’m gone.
Pollution is also a trade against future humans, though, including your descendants. We should really rebrand “Save the Earth” as “Save Humanity”. It’s pretty clear the Earth will survive us, as it survived the cataclysms that killed the dinosaurs.
The survival of my family now is implicitly required for survival of my lineage. There’s nothing you can say to change my mind based on environmental rhetoric.
With an average car tire weighing in at 12 kg or so, I find it surprising that they can lose something like half a kilo per year and still be useable after a half dozen years.
I suspect what’s going on is that heavy truck and bus tires are shedding the bulk of the mass.
I’m not sure if there’s a takeaway other than a preference for rail when all else is equal.
A medium size tire has ~5 square feet of surface area, so 3 or 4 square feet of tread. A tenth of an inch of wear on that surface is at least close to a pound of rubber.
This EPA study[1] (Pg 21) shows tire wear per mile has an inverse relationship to speed, but averages around 0.005g/km - 0.02g/km per tire. (NOTE: their table is per axle, front tires wear twice as fast)
20,000 km would be 100-400g per tire.
EDIT: Sorry, the units in the table shift from km, mi, single tire, axle, whole car, and it took me several tries to get the right numbers.
Yeah, in any case the paper gives smaller values than my estimate. It does use small vehicles though, at least relative to the last decades of production in the US (paper uses 1990s European sedans).
It's difficult as those are added to form tighter bonds in the rubber (Cd) and promote flexibility (Pb). Not sure the alternatives would be any less toxic.
Banning shit prematurely is how we ended up with solder/bump-gate when Europe prematurely banned leader solder and flaky wires when Apple dropped PVC in favor due to Greenpeace handwringling.
RoHS was great. Sure, there were a couple years when we all got sketchy electronics, but the technology fixing that was only developed because of the legal force applied.
One of the criticisms of RoHS was that even the companies that had exemptions were unable to exercise them because factories found it uneconomical to maintain separate production lines. If the EU had simply raised the cost, it would have been added onto the price and nothing significant would have changed.
If the tax attaches at point of production, the incentive is to use the output that is cheaper including the tax, or the best mix possible, shifting to less consumptive processes over time even if they can't meet demand at the start.
It depends on the visibility of the tax to the final consumer, and its long run salience.
Take water meters, a current topic in NZ. Some cities don't have them, some do. When I was last in the industry (over a decade ago) research had tended to show that after introduction of meters (usually with price rises) there was a reduction in per-household demand. But over the course of a few years this reduction vanished: households were back on their old water consumption trend. Water wasn't a big enough cost to matter either way.
(Commercial consumers have always been metered, so there isn't a lot of evidence there. Those I looked at had good reasons for using as much water as they did.)
If producers have to absorb the tax, things will probably work out as you say. If they can pass it along without losing much demand, maybe not.
I disagree that it has anything to do with visibility of the tax. If the government's goal is to reduce water usage, then all they have to do is increase the tax. If the usage doesn't go down, then increase the tax even more. At some point, the people paying for the water be unable to afford consuming the same amount of water, whether or not the tax is explicitly shown is irrelevant. If producers can absorb the tax, then keep raising the tax until the water consumption goes down.
Or you'll get more-and-deeper wells and a race to the bottom of the aquifer, as you see in California's central valley.
And of course folks will advocate for tiers and caps and exemptions and incentives and all manner of other mess to try and further distort the market to match their notion of fairness. Then everybody buying water will need to be a spreadsheet ninja to figure out how not to go broke while still managing to bathe.
The grandparent comment is advocating for sufficient levels of taxation to substantially change behavior, and I'm cautioning against unintended consequences of such a policy. I don't follow where the current cost of water is part of that discussion, but I welcome clarification.
> If the government's goal is to reduce water usage, then all they have to do is increase the tax.
A better way, that most governments in fact use, is to set performance standards that manufacturers of water-using appliances must meet, and progressively tighten those standards. Low-flow shower heads, aerating mixer taps, garden irrigation controls, low water use washing machines and dishwashers, and so on.
(And: tighten standards on local authorities/water utility companies also. Between 10% (in rich first-world cities) and 70% (in cities with colonial-era infrastructure) of water is lost due to leaks in pipes or pipe joints.)
If you wanted to go all big brother meters could be adapted to reduce flow rates after a certain daily consumption limit is exceeded.
A second possible alternative to taxation is "cap and trade". Every household gets a yearly allocation. Households wanting to use more buy part of the allocation of those that can use less. (Or grandparents donate them to their children while the grandchildren are at home.) Over time the cap reduces.
Both of those methods have less impact on poor people than simply increasing the price of an essential good.
Edit: all of this is fiddling around the edges when it comes to water, because the big consumer is agriculture. And governments almost without exception subsidize agricultural water consumption in one way or another. If they stopped doing that and imposed performance standards as with domestic usage, then agriculture would use water more efficiently.
But the water thing was just an example. For carbon taxes, the price increase has to be noticeable to the end consumer and explained as being due to carbon content, and reasonable alternatives have to be known to exist. (Which they now are, thanks in the USA mainly to Tesla. In Europe, there is public transport, and better urban design e.g. in Hidalgo's Paris.)
Those are all more complicated and more corruptible than just taxing the thing you want to reduce consumption of.
Helping poorer people is a separate problem, that has a very easy solution. Give them money. Of course, this is politically unpalatable as the costs are very transparent (and requisite increase in taxes for richer people).
Soldered connections don't last as long making products less repairable. Certain industries (e.g. aerospace) have wavers for these rules as connection failure could be fatal.
I'm glad those ROHS rules are in place but the tradeoffs are real.
Soldered Pb-Free connections don't last as long under what conditions? High-vibe? Large and frequent temperature excursions? High mechanical loading (high-mass components or bulky ones with leverage?) What solder are you using?
I think there's been a learning process since the adoption of Pb-free processes. Solder alloys have improved, package sizes have conveniently shrunk, you have underfill for BGA if necessary. Also when designing for high-vibe or large ∆temp, there's lab testing (shaker table, env. chamber) work that gets done esp. for safety-related hardware
Like, yes, Pb-free has considerations, but so does any other component of a system. I find that I usually don't have to give it much thought these days, and the fracture failures I've seen could have been mitigated by design changes rather than returning to Pb solder.
It's interesting that during the switch to Pb-free, other changes occurred in the electronics industry almost concurrently. Those were a switch to water based fluxes and cleaning processes, and a shift to production facilities in China, both of which involved a certain learning curve. I remember a year or two of boards with high failure rates, yet we looked and looked for things like solder whiskers to no avail.
The funny thing is the claim that the switch to PB free was some sort of sudden thing imposed on the industry from the outside instead of a 15-20 year long process where the industry have heavily involved in decision making. First rumblings I remember about phasing out lead was around 1988 or so. Same time they also had to deal with switching to surface mount packages and the phase out of Freon. The electronics industry didn't want the liability of having to deal with lead solder, lead contaminated waste, and worker safety. Seriously in 30 years I've never heard any complaints from the PCB manufacturers about phase out of lead. Only from people with no attachment to the industry.
No, but that argument is a bad for the same reason why it's bad when applied to climate change. No single lump of coal caused climate change, the problem is the avoidable harm in aggregate.
It's only a reasonable comparison if we're ignoring a large issue. I've spent the last 5 minutes looking for reports of failures due to tin whiskers, and mostly what I see is trade mag notes and essays from about 15 years ago that anticipate a coming plague of electronics failures from tin whiskers. If you have more info about the scale of the avoidable harm in aggregate, as you put it, I'd love to see it.
Anyone who has owned a car sporting summer tires can tell you how much some brands shed and it sticks to your car so you know a lot of it is ending up in the air. Which leads to the fact anyone driving a convertible can tell you the black grime you wipe off the interior of your car, much of it not noticeable until you wipe it down. Then top it all off with a healthy does of brake dust.
Summer blend tires did not used to be so prevalent but many sports sedans started to put them on to give the road grip that people expected. Then some tires run a bit soft to dampen road noise. So besides changing road surfaces the costs can be passed onto tire blends that are designed to shed. A few dollars on a price of a summer tire isn't going to be noticed considered their upfront costs usually are much higher than standard tires
Amid remaining uncertainty, one immediate low-tech alternative is rain gardens built at road runoff zones. Stormwater pools there, seeping into the earth, which filters out harmful particles before they can reach natural waterbodies. The SFEI team is sampling several rain gardens around San Francisco. One early test site shows a promising 90 percent reduction in particles, including tire fragments.
Why would tires contain cadmium or lead?
Here's a good tire recycling plant.[1] The process is straightforward. Chop up the tires, re-chop to smaller pieces, magnetically separate metal tire cords, grind up remaining rubber component, ship rubber to plant that makes rubber products, ship steel to steel mill.
Many videos of tire recycling plants on Youtube show inefficient operations. Big piles of partially chopped up tires, no reduction to a usable powder, no metal separation, not enough throughput. Serious operations have a front-end loader putting tires into the input hopper. Ones that look like subsidized demo plants have someone putting one tire at a time onto a conveyor. (They also tend to have names involving "Eco" and "Green". The serious players talk about tons per hour and the value of the product that comes out.)
[1] https://youtu.be/UWyLzXHqJSs