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    How good are American roads?

    (www.construction-physics.com)
    252 points chmaynard | 15 comments | | HN request time: 1.131s | source | bottom
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    rconti ◴[] No.42196461[source]
    > Interestingly, in all cases urban roads are worse quality than rural roads, presumably because they see higher traffic than rural roads.

    There's more infrastructure under urban roads. Crews come in to fix some utility, shred a section of a lane, patch it poorly with dissimilar materials, and leave.

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    vel0city ◴[] No.42196736[source]
    You're probably also going to have far fewer massive vehicles on those rural roads. More things like pickups yes, but probably considerably fewer semi-teicks and busses and fire trucks and cement mixers what not. Those big trucks passing through are going to stick to interstates far more often when going through rural areas.
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    1. FuriouslyAdrift ◴[] No.42196979[source]
    City buses are what really shred urban roads (and winter plows)

    https://www.kgw.com/article/news/verify/yes-bus-more-road-da...

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    2. vel0city ◴[] No.42197084[source]
    Yeah looking at any road around me it's obvious which lanes the busses prefer.
    3. PaulDavisThe1st ◴[] No.42197198[source]
    In the mid-90s, Seattle started excavating its bus-stops-on-a-slope and pouring a new concrete foundation, because the busses were warping the asphalt so badly.

    I was just back there this last weekend, and you can no longer see any of the concrete - it has all been coated with asphalt. However, I assume its a rather thin layer because none of the bus stops I checked show the signs of damage that were becoming common in 90-96.

    replies(2): >>42197551 #>>42197925 #
    4. wombatpm ◴[] No.42197551[source]
    They opened a new truck stop near me with asphalt roads. 6 months later they tore it up for concrete because the asphalt shifted into lumps where the trucks were turning cono
    5. mlsu ◴[] No.42197867[source]
    This is a reason why buses are not as cheap as they seem at first glance.

    Often times, buses are favored because they require low capex (adding lines is easy, politically palatable, etc).

    But in practice, on really busy bus lines with high throughput, it shreds the roads, to the point where you really need to re-pave the whole road every 10 years -- in which case, why not just put a rail line in and use a train!

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    6. teh_klev ◴[] No.42197925[source]
    I did google "bus-stops-on-a-slope", but nothing jumped out. What are "bus-stops-on-a-slope"?
    replies(2): >>42197973 #>>42198626 #
    7. ender341341 ◴[] No.42197973{3}[source]
    I think they meant that the bus stop is on a hill maybe?
    8. animal_spirits ◴[] No.42198141[source]
    That is similar to the reason trackless trams are not economically viable. They are essentially just busses that are guided, but because of their precision the cause really bad erosion on the parts of the road where they drive. At least with busses there is variability on the parts of the road that are eroded and it affects the whole road more evenly
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    9. entropicdrifter ◴[] No.42198459{3}[source]
    There are certain places/conditions where trackless does make more sense, however. Philadelphia still has several trolleybus lines active for instance, in addition to buses, trolleys, subway, el-train, and traditional rail.

    My guess is that it works here because our roads turn to shit anyhow from the freeze/thaw cycle, so it's not adding as much maintenance burden as it would elsewhere.

    10. stonemetal12 ◴[] No.42198626{3}[source]
    Asphalt, like glass, is an amorphous solid. When a heavy truck sits still on asphalt, asphalt will flow out from under the tires. Not only do you get a depression and eventually a pot hole where the tire was, and you get a little hill next to it.

    You just about need an offroad vehicle to avoid hitting the street.

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    11. PaulDavisThe1st ◴[] No.42198885{4}[source]
    Moreover, when a heavy vehicle like a loaded passenger bus has to accelerate from stationary on a hill, it exerts incredible force on the asphalt below it.
    12. tallanvor ◴[] No.42204528[source]
    Assuming you don't have the ability to separate traffic, you don't really gain anything. Cars have to be able to drive in the same lane, so the tracks have to be level with the roadbed and asphalt gets torn up very quickly along the tracks.
    13. asdff ◴[] No.42205241[source]
    Usually they pave the bus stop as cement and then its fine
    14. asdff ◴[] No.42205262{4}[source]
    Doesn’t just happen on hills you can see this phenomenom on flat intersections too that have seen a lot of nearby construction vehicles (cement trucks, dump trucks, etc are probably the worst).
    15. cassepipe ◴[] No.42213174[source]
    Maybe the fact that every car in the US weighs two to three times more as it needs doesn't help either. I'd be curious to get the numbers to see what's worse. A half packed bus every 15 minutes or thousand of pickup trucks.