<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>bigiain</author><text>&amp;gt;They&amp;#x27;re torn up from the road and rubbed off from the tyres themselves. The majority is obviously coming from the road.&lt;p&gt;Not sure even that adds up to believable.&lt;p&gt;The Sydney Harbour Bridge is about 500m long between the pylons. It has &amp;quot;more than 150,000 cars per day&amp;quot; on it (according to the snippet from a google search). If all of that was from the road, that&amp;#x27;d mean there&amp;#x27;s about 160 tons of road getting torn up per year. It looks to be ~30m wide on Google Sat view, and &amp;quot;google first hit&amp;quot; research indicates road base weighs 1.9tons per cubic meter. It&amp;#x27;s be losing almost 6cm of depth along the whole span every year if all those numbers hold, or 3cm per year if &amp;quot;only half&amp;quot; of that comes from the road and the rest from the tires. They don&amp;#x27;t resurface it anything like often enough for that to be true...</text><parent_chain><item><author>kungtotte</author><text>They&amp;#x27;re torn up from the road and rubbed off from the tyres themselves. The majority is obviously coming from the road.&lt;p&gt;There&amp;#x27;s been studies done here in Sweden since we&amp;#x27;ve banned studded winter tyres in some areas of Stockholm in an effort to reduce road wear and improve air quality. I don&amp;#x27;t know of any sources in English off the top of my head though.&lt;p&gt;The last time I read an article about it though (2+ years ago, during Diesel-gate), the findings was that the danger in the particles comes from their size with smaller particles being more dangerous for humans. And that road particles were something like an order of magnitude larger than exhaust fume particles from diesel engines.&lt;p&gt;We&amp;#x27;ve since banned diesel engines inside Stockholm as well so the whole thing is moot here.</text></item><item><author>ratel</author><text>Hold on:&lt;p&gt;The claim is this:&lt;p&gt;&amp;gt; &amp;quot;Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles.&amp;quot;&lt;p&gt;It does not seem to be a mistake:&lt;p&gt;&amp;gt; &amp;quot;Compared with regulated exhaust emission limits of 4.5 milligrams per kilometer, the completely unregulated tyre wear emission is higher by a factor of over 1,000.&amp;quot;&lt;p&gt;A tire might way up to 15 kilograms for a 20 inch type. Lets assume 10 kilograms for a normal tire which is on the high side. 4 tires is 40 kilograms. Even if we assume half of the particals are not coming from the tire (but from where?). That still leaves 40,000 &amp;#x2F; 2.9 = 13793 kilometers for the tires to be completly consumed (weighing nothing anymore). That is definitely not happening.&lt;p&gt;So without an explanation on where the matter is coming from this does not read right.</text></item></parent_chain></comment><story><title>Pollution from tire wear is worse than exhaust emissions?</title><url>https://www.emissionsanalytics.com/news/pollution-tyre-wear-worse-exhaust-emissions</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>saiya-jin</author><text>That doesn&amp;#x27;t make sense to me either. Take a busy German highway (as I don&amp;#x27;t know the average load on US ones), easily 100k cars per day. There are parts of highways which don&amp;#x27;t get replaced for 20 years easily. Plus apart from tiny fraction of north europe (and maybe Canada?), nobody ever uses studs.&lt;p&gt;Back of the envelope math tells me 1 km of highway would lose some 730 tonnes of asphalt, per year (so 14,600 tonnes in 20 years).  If we talk about normal car wear, this simply isn&amp;#x27;t happening on those unkempt roads. It would leave huge lanes of deeper surface where asphalt is lacking. There isn&amp;#x27;t visible wear on lanes that are used mostly by cars like that. Roads have mostly potholes.&lt;p&gt;What happens on those roads is, sticky asphalt is worn away (but not at the mentioned rate), and what remains are stones which basically don&amp;#x27;t wear, and tires touch only that. At least highway surface I saw was like that.&lt;p&gt;What damages roads greatly are trucks, especially overloaded ones (say limit is 15 tonnes, they take 22 tonnes and hope to not be checked... welcome to east european mentality).</text><parent_chain><item><author>kungtotte</author><text>They&amp;#x27;re torn up from the road and rubbed off from the tyres themselves. The majority is obviously coming from the road.&lt;p&gt;There&amp;#x27;s been studies done here in Sweden since we&amp;#x27;ve banned studded winter tyres in some areas of Stockholm in an effort to reduce road wear and improve air quality. I don&amp;#x27;t know of any sources in English off the top of my head though.&lt;p&gt;The last time I read an article about it though (2+ years ago, during Diesel-gate), the findings was that the danger in the particles comes from their size with smaller particles being more dangerous for humans. And that road particles were something like an order of magnitude larger than exhaust fume particles from diesel engines.&lt;p&gt;We&amp;#x27;ve since banned diesel engines inside Stockholm as well so the whole thing is moot here.</text></item><item><author>ratel</author><text>Hold on:&lt;p&gt;The claim is this:&lt;p&gt;&amp;gt; &amp;quot;Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles.&amp;quot;&lt;p&gt;It does not seem to be a mistake:&lt;p&gt;&amp;gt; &amp;quot;Compared with regulated exhaust emission limits of 4.5 milligrams per kilometer, the completely unregulated tyre wear emission is higher by a factor of over 1,000.&amp;quot;&lt;p&gt;A tire might way up to 15 kilograms for a 20 inch type. Lets assume 10 kilograms for a normal tire which is on the high side. 4 tires is 40 kilograms. Even if we assume half of the particals are not coming from the tire (but from where?). That still leaves 40,000 &amp;#x2F; 2.9 = 13793 kilometers for the tires to be completly consumed (weighing nothing anymore). That is definitely not happening.&lt;p&gt;So without an explanation on where the matter is coming from this does not read right.</text></item></parent_chain></comment><story><title>Pollution from tire wear is worse than exhaust emissions?</title><url>https://www.emissionsanalytics.com/news/pollution-tyre-wear-worse-exhaust-emissions</url></story>