The snow exposed to cars is covered in grimy residue, while the snow away from traffic remains clean.

  • zr0@lemmy.dbzer0.com
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    1 day ago

    That rationale is just stupid. It is indeed a lot of dirt, as every tire caries dirt and many tires = many dirt.

    Of course it also includes the other shit. I am just not so sure about the claim that “this is no dirt or else it would be also visible on the top road”

    • bstix@feddit.dk
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      13 hours ago

      I think the point could be stated more clearly by only using the bottom picture.

      The snow that is scraped from the road is dirty, while the snow from the pavement is … less dirty. It might be dirt or exhaust or whatever. Roads and pavements are just filthy.

      More interestingly, if you live in a place where the piles don’t thaw quickly, you can watch the road side of the snow getting progressively more dirty from the ongoing exhaust even if the road is not scraped afterwards. At the end of the season, the roadside snow piles will look charcoal black. It’s most noticable at crossings where cars run the engines at red light. Had it all been just dirt, it would look the same everywhere along the road, but it doesn’t.

    • Pyr@lemmy.ca
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      21 hours ago

      I’m not denying that cars are dirty either, but it’s also easy that the bottom pic could look like the top pic and vice versa based on when the photos are taken. Timing of the snowfall, if one road gets sanded/salted and not the other, etc.

    • Mr_WorldlyWiseman@lemmy.blahaj.zone
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      23 hours ago

      In places where lots of people walk, the snow is white. In places where people cross a road, the walking paths leading from the crosswalk are brown.

      The “dirt” comes from cars and is highly toxic.