[HN Gopher] What are those dents in I-90 outside Seattle?
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What are those dents in I-90 outside Seattle?
Author : haossr
Score : 69 points
Date : 2022-12-30 19:32 UTC (3 hours ago)
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(TXT) w3m dump (boards.straightdope.com)
| landr0id wrote:
| I asked the WSDOT the same question a while back:
| https://twitter.com/landaire/status/944698354742599681
|
| "The dowel bars help extend the life of the pavement by about 10
| years or so."
| idatum wrote:
| Only slightly related, about I-90 generally:
|
| A parent of mine who grew up and lived most of their life on the
| East Coast, US, visited and we drove east across WA. At one point
| they could not wrap their head around the fact that we had been
| travelling at around 80 mph for 2 hours. And it basically looked
| the same out the window :)
|
| The US West is huge.
| rootusrootus wrote:
| There are a number of areas out in eastern Washington where the
| state patrol doesn't often bother with speed enforcement and
| people routinely go even faster. It is common to have packs of
| cars going up the left lane over Manastash Ridge at closer to
| 100 mph. With a closure rate of about 70 mph on the trucks in
| the right lane. One way to make an otherwise monotonous drive
| more interesting.
| jasonhansel wrote:
| > Maybe they didn't use the best grout and that's wearing away
| faster than the surrounding concrete.
|
| IIRC this is one of the disadvantages of concrete (as opposed to
| asphalt) road surfaces: it's very hard to repair them in ways
| that don't degrade over time.
|
| edit: You can tell this road is "real" concrete because of the
| visible seams between each slab. For an ideal repair, they would
| have had to replace _every affected slab_ of concrete, which
| is...all of them along this stretch.
|
| You don't see these concrete road surfaces much near where I live
| (in Boston), particularly because such roads are much less safe
| when snow and ice are present.
| egberts1 wrote:
| Dowel Bar retrofit.
|
| Details on how to make a set of dowel-bar-retrofits.
|
| https://dot.ca.gov/programs/construction/construction-manual...
|
| Longitudinal grooving to achieve PIARC category of roughness and
| rolling resistance of an inverse to raised Cat's-Eye and Botts'
| Dots ("turtles" in Washington/Oregon, "buttons" in Texas). They
| are reflectorless, and are
|
| https://www.fhwa.dot.gov/pavement/pubs/hif17011.pdf
|
| Not to be confused with Rumble strips which are also known as
| audible lines, sleepy bumps, wake up calls, growlers, drift
| lines, waker-uppers and drunk bumps.
| unixhero wrote:
| A forum! How refreshing.
| quickthrower2 wrote:
| Looks like a discourse.org one
| legitster wrote:
| Man, reading this format does not make me miss forums.
|
| It's easy to opine for the "internet of old", but I for one do
| not miss having to post a car problem to a Ford Escort message
| board and maybe getting an answer after 3 days of being told I am
| an idiot.
| lostlogin wrote:
| Now you can get that response in minutes or even seconds, and
| in a more readable format with push notifications and
| advertising.
| [deleted]
| osti wrote:
| I always thought it was to help with traction during winter...
| They are only present outside the city afaik.
| dbavaria wrote:
| They're present in the city too, here are some in Seattle:
|
| https://maps.app.goo.gl/2j5H4gEXKrRVFr469
| modeless wrote:
| I haven't seen these in a decade but I knew what they were
| talking about instantly. I used to wonder what they were all the
| time. I sure didn't expect to get an answer randomly on the HN
| front page.
|
| They did a really good job installing these. They look like they
| would be bumpy but I never felt them at all.
| vl wrote:
| >They did a really good job installing these.
|
| It really depends on the car and suspension! In regular car
| driving over them is fine. In motorhome vibration is so strong
| that I go in the left lane, otherwise it's two hours of crazy
| shaking.
| modeless wrote:
| This was a decade ago. Perhaps the replacement concrete is
| wearing away now.
| frosted-flakes wrote:
| Similarly, I'm always impressed by how smooth the ashpalt
| highways in Toronto are, even though they are spiderwebbed with
| cracks absolutely everywhere. That's because the cracks are
| filled each spring with some sort of sealant. They make a
| regular slapping sound as the tires pass over them, but cannot
| be felt.
| lostlogin wrote:
| I don't think you could do the repair with asphalt. I'm not
| even sure I've ever driven on a concrete road, as down here
| in New Zealand there aren't any I don't think.
|
| The current repair practice is to pour tar on the asphalt
| road and then a coating of road gravel. It's noisey, comes
| off when heavy vehicles use it, comes off with heavy usage or
| heavy breaking, comes off in hot sun and it's utter trash.
| It's cheap though!
| frosted-flakes wrote:
| Of course they don't add rebar to asphalt roads, that would
| be ridiculous. The sealant process is done manually, with
| some poor sod pushing a machine along each crack and
| injecting hot sealant which prevents further water
| incursion and the associated frost heave. That's partly why
| I'm so fascinated with it: some sections of highway are
| cracked _everywhere_ , with hardly a square metre that
| doesn't have a crack running through it, and yet they're
| extremely smooth.
| LegitShady wrote:
| you are describing an asphalt microseal over the entire
| road surface. they are describing sealing of cracks using
| asphalt "tar snakes". They address different problems.
|
| Road resurfacing improves stopping distances and rough
| rides if the road is overall in ok condition. If the road
| has large cracks in it this does nothing
|
| Tar snakes are used to seal cracks from water because after
| rain the movement of vehicles over the wet subgrade under
| the road creates a pumping effect that ejects subgrade
| material out from the cracks and causes potholes in the
| future.
| Maursault wrote:
| I don't understand how everyone knows what the commenter is
| referring to when it took me forever. I figured he was referring
| to the "dents" on the shoulder, which I thought were rumble
| strips.
| fckgw wrote:
| If you scroll up to the top of the thread the OP posted a
| little ASCII diagram of what they were describing
| mbauman wrote:
| A little funny to not link to the comment that had the answer --
| they're dowel bar retrofits.
|
| https://en.wikipedia.org/wiki/Dowel_bar_retrofit
| haunter wrote:
| If a Wikipedia page about a technological topic (so not a
| person, place etc) has a very few languages available (in this
| case 2) then it always makes me wonder how other countries in
| the World solve the same issue. This seems like a very US thing
| for example but maybe I'm wrong
| the_mitsuhiko wrote:
| I was wondering the same thing recently. In Austria and some
| countries around a pretty popular road replacement system is
| called "fly over"[1] which has nothing to do with an overpass
| in the US, but is basically a small bridge put on top of a
| highway to repair the road surface underneath without
| interrupting traffic.
|
| It was mislinked on Wikipedia to overpass and while trying to
| figure out what it should link to I learned that this concept
| just does not really exist in other countries.
|
| [1]: https://www.waagnerbiro-
| bridgesystems.com/references/fly-ove...
| goodcanadian wrote:
| My understanding is that concrete is generally not used for
| highways in Canada because it doesn't hold up well in the
| yearly freeze-thaw cycle that the majority of the country
| experiences. Asphalt is used as it is more flexible, and also
| easier to repair (generally just filling cracks with tar)
| when the inevitable frost heave damage occurs.
|
| Concrete is more durable (but it still needs to be
| maintained) and that is probably why it is used in parts of
| the U.S. where this is less of an issue. I can't make much
| comment on what other countries do though I have only noticed
| concrete roads in the US.
| rootusrootus wrote:
| Maybe this is true. But honestly, we don't have that many
| roads in the PNW that are concrete. It was when I lived in
| the midwest that I noticed them _everywhere_. I really don
| 't care for them. In the PNW we have relatively few, but
| the weather here is milder than the midwest. Not sure what
| that says about the freeze-thaw hypothesis.
| frogulis wrote:
| Mostly asphalt here in Melbourne. No freeze-thaw cycle, but
| anecdotally the few concrete roads I have driven on are
| pretty rough and the repairs don't appear to be very
| effective.
|
| (Westall road outside the ikea and Dandenong road in
| Caulfield where it goes under the train line)
| Jorengarenar wrote:
| Until now, I wasn't aware USA makes highways with concrete.
| As far as I know, in Poland vast majority of paved roads is
| made with asphalt, rarely bricks.
| rootusrootus wrote:
| The vast majority of paved roads in the US are asphalt.
| HyperSane wrote:
| Only the busiest roads are made with concrete. Most roads
| are asphalt.
| JoBrad wrote:
| In Middle TN, at least, asphalt is coming back in favor.
| Apparently concrete doesn't handle the freeze/thaw cycle
| very well, and is harder to repair than asphalt.
|
| In a side note, TN Department of Transportation recently
| experimented with a more porous asphalt variant on some
| major roadways, which was supposed to help with drainage.
| But in the winter, rain soaked deeper into the porous
| asphalt, causing much larger pot holes than expected. They
| repaired this with more traditional asphalt, which really
| stands out next to the more porous type, when it's raining.
| I don't know what the final fix will be, but it seemed odd
| that they wouldn't have tested that scenario more fully.
| kube-system wrote:
| It depends on the use. Both asphalt and concrete are widely
| used in the US, depending on the engineering demands.
| voidfunc wrote:
| Depends where in the USA you are. Most of the Northeast is
| asphalt.
| garaetjjte wrote:
| Some highways (eg. east part of A2) in Poland are concrete
| too. (not to mention post-German concrete highways, but I
| think they are already gone)
| wkat4242 wrote:
| In the Netherlands we don't use concrete plates. Just
| asphalt, usually the highly absorbent type. It wears very
| quickly and ice buildup damages it so it gets replaced a lot.
|
| But this is the advantage of a small country with many
| people. Good infrastructure.
| nemo44x wrote:
| Many roads are composite here. They have a sub-road made of
| reenforced concrete that creates a stable layer and then
| asphalt is laid on top. Because the asphalt wears out it is
| easily ripped off the concrete layer and repaved.
| rootusrootus wrote:
| In the PNW we commonly use porous asphalt (so the rain
| doesn't build up and cause hydroplaning) as well. A few
| interstates still use concrete. I wouldn't be surprised if
| that had something to do with weather and related
| maintenance requirements. I-90 being a pretty good example.
| Gordonjcp wrote:
| There's one bit of jointed concrete road that I know of in
| the UK, a few miles where I live on the A90 near
| Laurencekirk.
|
| It's bloody awful, like driving over smashed paving slabs. In
| my big old Range Rover with its off-road air suspension and
| massive reinforced tyres it's a noisy and uncomfortable
| couple of miles. In a modern vehicle with ultra-low profile
| tyres and incredibly stiff "sporty" suspension it must be
| like being rolled down a hill in old washing machine.
|
| So yeah it's entirely possible that it's a very US thing,
| I've never seen it anywhere else.
|
| Edit: here you can see a section, with repairs showing up as
| dark lines across it.
|
| https://www.bing.com/maps?osid=55db8ed6-35d8-4916-82c3-14131.
| ..
| bombcar wrote:
| The US interstate moves insane numbers of huge ass-trucks
| that weight one billion metric pounds each or something.
|
| Anything less than airport-grade concrete dies instantly,
| and then dies again when it invariably freezes to -40deg
| Kelvin, because fuck physics when shit gets cold.
| Ancalagon wrote:
| I love the hyperbole in this comment! :D
| usrusr wrote:
| Allow me to single out the metric pound, which is defined
| as precisely a billionth of the weight the local road
| surface can withstand. Noteworthy for being one of the
| few units that work for both mass and weight because the
| local gravity is conveniently factored in.
| WalterBright wrote:
| The reason for the interstate trucks is the taxation
| system that punishes railroads for owning their right-of-
| way. The trucks cause by far the most damage to the
| highways, but taxpayers subsidize that with the gas tax.
| Trucks also do not pay property tax on the highways.
|
| Long haul freight should be done by loading the semi's
| trailer onto a flat car, and picking it up near the
| destination.
|
| Another myopic government decision is to try to replace
| the diesel trucks with electric ones, you know, for the
| environment. Far better for the environment would be to
| do away with long haul trucking and use freight trains
| instead, which are far more efficient. Trains also do not
| spread tire and brake dust all over the place, either.
| nemo44x wrote:
| The USA has possibly the best freight rail system in the
| world and it's used extensively. Trucks pay a ton of
| tolls, licenses, and fuel tax.
| engineer_22 wrote:
| Trucks pay much higher tolls. Tolls are based on axles
| and weight.
| josephcsible wrote:
| But not nearly higher enough. Driving on roads damages
| them in proportion to the fourth power of per-axle
| weight, which is about 17,000lbs for a fully loaded semi
| and 2,000lbs for a car. To put that in perspective, if
| the toll for the car were $0.25, it'd have to be over
| $1,300 for the truck for it to be fair in that sense.
| nemo44x wrote:
| It will just raise shipping costs and therefore raise the
| cost of goods. By charging trucks more it creates a
| regressive tax effectively. By subsidizing them this is a
| way we utilize socialism to ensure lower wage people have
| access.
| fredoralive wrote:
| There's an interesting blog post about the UK's unloved and
| out of fashion concrete Motorways here:
| https://www.roads.org.uk/blog/diamond-rough which notes
| that the US seems to occasionally grind the surface of
| concrete roads, whilst in the UK [INSERT WHATEVER THE
| HIGHWAYS AGENCY IS CALLED THIS WEEK][1] don't (barring
| recent trials) leading to people driving on rough decades
| old surfaces. Although ISTR it was the expansion joints
| that were the real annoyance? But I haven't personally
| encountered concrete roads in the UK in decades, it's more
| of a thing from when I was a kid.
|
| [1] Or local / devolved authorities etc.
| dang wrote:
| The submitted URL was https://boards.straightdope.com/t/what-
| are-those-dents-in-i-... but our software replaced it with
| https://boards.straightdope.com/t/what-are-those-dents-in-i-...
| because that's what the page says is its canonical URL. I've
| reverted it now.
| gpvos wrote:
| But the top comment at the /30 URL is not the actual answer
| either...
| vl wrote:
| Looks like filler is gone from these on I-90 because driving in
| motorhome over them (V-8 F-53 chassis) leads to crazy
| vibration. Regular car is fine.
| rootusrootus wrote:
| That's interesting, I'd never have guessed. They always seem to
| be just the right lane, so I figured there must be some other
| explanation.
| insane_dreamer wrote:
| I didn't know what purpose they served but I can tell you they
| are nasty if you hit them with their bike at speed; almost had a
| serious accident when moving out of the lane and over to the
| narrow shoulder to let cars by me pass (this was on a small
| 2-lane road through a pass, not a highway of course), didn't
| realize how deep the dents were and almost lost control of my
| bike
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