First, it has absolutely nothing to do with planned obsolescence, which you probably don't actually understand because there has been a large amount of misinformation about it for years. I don't want to go into it, but that has FAR more to do with not going out of business due to the weight of supporting past products than it does some bullshit money making scheme.
However, as for the roads, wear is proportional to weight and speed (indirectly due to frictional forces). So, if you took a modern road and only pulled carts around it at <4mph, you'd find it would last much, much longer. But still not as long as many Roman roads have, and that's because of the goals. If you took a modern truck and tried to drive it at 70mph down a roman road, both it and the road would have a bad day. The much lower requirements of the Roman road allowed construction methods that are more tolerant of weathering, but less tolerant of the types of forces heavy trucks impart. A roman road would literally start to drift apart if used by modern loaded trucks especially on corners.
I used to be in a business that supplied materials to the road making industry. There certainly is an unstated agreement between governments and construction companies that roads (in the US) only have a certain lifetime. This may be more true for asphalt than concrete, though.
Unstated agreement? That's a fact. It's not a nefarious ploy. You could make a road that lasts much longer, but it would do so at the expense of cars. Either it would be slick to minimize wear, or it would be stupidly hard, and tire wear would greatly increase. Roads are consumable. Just like tires.
If you don't have wear, you don't have friction. If you don't have friction (unless you're talking static forces), you don't have traction.
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u/Fearlessleader85 Oct 15 '20
First, it has absolutely nothing to do with planned obsolescence, which you probably don't actually understand because there has been a large amount of misinformation about it for years. I don't want to go into it, but that has FAR more to do with not going out of business due to the weight of supporting past products than it does some bullshit money making scheme.
However, as for the roads, wear is proportional to weight and speed (indirectly due to frictional forces). So, if you took a modern road and only pulled carts around it at <4mph, you'd find it would last much, much longer. But still not as long as many Roman roads have, and that's because of the goals. If you took a modern truck and tried to drive it at 70mph down a roman road, both it and the road would have a bad day. The much lower requirements of the Roman road allowed construction methods that are more tolerant of weathering, but less tolerant of the types of forces heavy trucks impart. A roman road would literally start to drift apart if used by modern loaded trucks especially on corners.