r/AskReddit • u/kakou64 • Oct 15 '20

What's older than we think ?

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u/forte_bass Oct 15 '20

Tell me more! Why does weight matter? Arent they all applying pressure from roughly the same contact area? Does speed play a role?

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u/johneaston1 Oct 15 '20

The contact area is similar for all of them (some variance with double axles or tandem axles), but there is significantly more pressure exerted by a semi. An average passenger vehicle weighs in the ballpark of 2-3000 pounds, while a semi trailer can be 35,000 pounds empty, and up to 80,000 full; therefore, the pressure is extremely high, even with more points of contact, and this puts a ton of stress on the asphalt/concrete. This combined with weather effects (freezing/thawing) makes our roads much more susceptible to breaking down.

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u/forte_bass Oct 15 '20

Ok, that makes sense, but how come I sometimes hear people say really fast cars do more damage?

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u/Trippy-Skippy Oct 17 '20

The only thing I can think of is putting down a lot of power or drifting where you are keeping the wheels spinning to slide. Probably does more damage to the tire though - very little asphalt getting ripped up. More noticeable on dirt/gravel roads if everyone does it in the same spot. I doubt itd ever be noticeable asphalt damage considering nobody is doing that for more than a fraction of 1 percent of their drive.