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noblergt posted:Streetview just updated in the UK to cover almost every single road, so I can share that we have this in Jolly Old England as well! (since I can finally get street view in areas in familiar with) Yeah, I remember reading about Twyford Down. I'm surprised the project made it; most projects here that run into environmental issues get canceled. A Field Trip The weather was great yesterday, so I took a state car around to some projects to see how things were going. First stop was Killingworth, to check out the roundabout we built there about a year ago. It's the crime-fighting roundabout, if you remember my story from the last page.  Well, that doesn't look so bad at first glance. For some reason, the designer decided to go with raised, non-mountable islands made of stamped, stained concrete.  Since the islands are made of concrete, we can't bury the signs in them, or else we'd need to re-pour it every time they're replaced. Instead, we put in PVC sleeves and backfilled with sand. How did that work out?  Oh... not very well at all. Let's look at the pavement markings.  We went with a dashed line for the yield bar, but I'm hoping the next roundabout will have shark teeth. They look so much cooler. But what're all those little sticks on the ground?  Oh... those orange (why orange?!) delineators, supposedly fracture-proof, got run over a couple times and snapped like twigs.  The stamped concrete truck apron looks suspiciously like a sidewalk, and is very inviting to peds, so we had to put up signs telling them to keep off. Someone also put warning and regulatory signs on the same post, which is a no-no.  Boy, that concrete's not holding up well at all. Despite being something like 18" thick, plows just beat the crap right out of it. These islands will be mountable before too long.  Welcome to Killingworth, home of perpetual construction. These guys aren't even holding the signs right. Next stop, Groton! Let's hope things suck a little less there.  Yessiree, these sign supports (and the bridge on which they're mounted) are in great shape! No way they could possibly break! Note also that the signs themselves are bent from being hit so many times.  This one's even got a big old bullet hole in it. That impact crater is about 3" in diameter, if you're unsure of the scale. Also, overhead signs are huge. Next, off to East Haddam!  This is not what I'd call an orderly and straightforward work zone. Even the "Stop Ahead" sign is out of spec.  Wh... ok, there are two things wrong with this sign. One, it's the wrong color. Two, it's sending state traffic down a local road! Very very bad. I'm just going to pretend the town got an encroachment permit and put it up at its own expense... And one quick stop at Colchester to check out a bridge!  Yeah, this thing isn't in good shape. Concrete's hosed, steel's hosed, good thing we're... re-painting it.  But I got to drive around a wheel! Yaaaaay!   Bonus shot: Way to keep an eye on traffic while you're walking down the middle of a freeway, buddy. 10-megapixel versions of any of these photos are available if you like!
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Mar 12, 2010 00:04
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Field trip owns. Please post another one!
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Mar 12, 2010 00:46
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Yes that was interesting, please post more! Then I'll have something to show to people who complain about the roads here...
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Mar 12, 2010 00:59
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Sure, I have a couple more pictures. I'll get some I took of a previous field trip tomorrow. If I'd known you guys liked it so much, I'd have taken my camera along on all of them! Yes, it's my personal DSLR. The state hasn't bought new cameras since floppy diskettes were in vogue. There's a close-up of the patterned concrete. It really doesn't look bad, and it lasts a lot longer than real brick. Like I said, though, it's mighty inviting to peds. The tire skidmark in that pic shows just how dangerous that can be.  This shows the average condition of our signs (and bridges). For some reason, red fades much faster than the other colors, so the "INTERSTATE" part at the top of the route shield is completely faded. Yes, that's supposed to be red. Also of note, a bunch of the reflective buttons have fallen off, the "ONLY" plaque's not retroreflectorized (and therefore invisible at night), and whatever hit this sign probably hit the bridge as well.   Don't mess with DOT flaggers; they're hard as nails and will beat the poo poo out of you with their lollipops, WITHOUT EVEN TAKING THEIR HANDS OUT OF THEIR PANTS!  "Hey, boss, there's a little culvert end here. Should I do something?" "Yeah, sure, slap a coupla object markers on it." "But it's 30' back from the road..." "Whatever, just make them face the wrong direction and we'll pretend it makes sense." (It's for lawnmowers, not cars  )One more thing of note: as I was heading down Route 9, nearly every sign had exactly one character that was orange instead of white. I don't know if that was someone's idea of a joke or what, but once you notice it, it's really bizarre.
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Mar 12, 2010 01:35
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Cichlidae posted:
I had no idea what those things were called. Object markers, huh. What's their normal intended use, if this setup is apparently improper? Also something cropped up in my daily commute that's kind of befuddled me. At one point I pass through a big 4-way intersection with a light, going straight and then immediately taking a left at the next light. This second light is a T intersection with the road joining from the left, and from my approach the light used to be either red, green (permissive left), or green with a left arrow (protected left). Recently they redid the light so the normal green phase also has a red left arrow, essentially eliminating the permissive left option. I'm wondering though, what was the point of the change? A lot of traffic makes that left turn and I've seen the queue to make that turn back up almost into the prior 4-way intersection at busy times. If anything I thought they'd want to allow a higher throughput on the left turn, but by eliminating permissive lefts on the green phase it seems like less people will be able to get through. Unless there were people getting hit all the time making that left, I don't see the logic in it. And I kinda doubt that's the case since visibility of oncoming traffic is quite good from that spot.
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Mar 12, 2010 05:52
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Nibble posted:I had no idea what those things were called. Object markers, huh. What's their normal intended use, if this setup is apparently improper? It's technically not improper, actually. Like I mentioned, the object markers are for off-roaders and lawnmowers. If there's snow or high grass, they'd have no other indication that there's something that could wreck their vehicle. When the object marker is placed on the roadway, it's called a delineator instead, and it's used to mark the edge of the roadway for increased visibility. quote:Also something cropped up in my daily commute that's kind of befuddled me. At one point I pass through a big 4-way intersection with a light, going straight and then immediately taking a left at the next light. This second light is a T intersection with the road joining from the left, and from my approach the light used to be either red, green (permissive left), or green with a left arrow (protected left). Recently they redid the light so the normal green phase also has a red left arrow, essentially eliminating the permissive left option. I can't say for sure without looking at the intersection. Usually, a state will have a policy on when lefts should be protected-only. Sight distance is one factor, also number of lanes and oncoming volume. A string of left-turn accidents (or one high-profile accident) would have the same effect.
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Mar 12, 2010 13:13
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noblergt posted:Twyford Down curring, the main reason that motorway construction for the past 10 years has been so abysmal. (info I'm suprised they pissed and moaned about that little cutting and not this bad boy. But yeah, thanks to Twyford Down, motorway building in england now means that we are apparently raping the countryside and everyone should be forced to use the aging infrastucture we are left with! 
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Mar 12, 2010 16:38
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It wasn't the cutting itself, its that it went through part of the East Hampshire Area of Outstanding Beauty, was an ecologically rich area, and it did destroy a large area of chalk downland, went straight through a site of special scientific interest. The plan wasn't originally the cutting, instead it was going to go around the hill to the west  Click here for the full 968x636 image. However the land was owned by Winchester College who refused to sell the land because it was a water-meadow. Then the government assessed whether a tunnel would be a good idea, but decided it was too expensive. So a cheaper cutting was announced, and the protests were massive, but they slowly dwindled as the work was completed. The cost of dealing with the protesters was very high however, and it probably would of been cheaper to build a tunnel overall! Also in that map you should be able to see where the original 1940 bypass went nozz fucked around with this message at 19:55 on Mar 12, 2010 |
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Mar 12, 2010 19:52
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Here's some more field photos from nearly a year ago. First off was Manchester, the second-manliest town in Connecticut, after Mansfield.  Well, I certainly hope those signs aren't too important... also note the "when flashing stop ahead" sign comes before the "signal ahead" sign. What? Heck, they even put a warning and a regulatory sign on the same post.  A plethora of lane use signs! I think there were 8 in total, including the span-mounted ones, just for this one approach. That'll give you an idea of the queue lengths, too. Also note that the through lane actually is off to the left. Both of the previous through lanes become right-turn-only lanes.  Round two of "check your sign placement."  Who needs "No Turns" signs when you've got these puppies?!  That span wire must feel like Atlas. It's holding at least 17 signal heads (they weigh more than I do), 8 18"X24" signs, and 4 video detection cameras. Next up was East Haddam, the same project as this one:  This is how we close a broken bridge. Rows of barricades, concrete blocks, and drums. Despite all that, the locals would still move things around and continue driving over the bridge (on the verge of collapsing!) to avoid a 1-mile detour. We even got an angry letter from a local cleric (with 200 signatures from his parish) telling us how we should re-open the bridge because the detour route was too dangerous.   And the detour route created an extended wrong-way concurrency between 149 and 151! Kickin' rad.  This is what a sign panel looks like up close. You can see the individual little lenses that make it up. The overlaid shape (hexagon in this case) tells you which grade of sheeting it is.  This picture is taken from nearly the same angle as the one thumbnailed above. What a difference a year makes! I'll take another one in 2011 for a nice triptych. That's it for that trip. Not as interesting, perhaps, but I promise the next will be even better.
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Mar 12, 2010 23:13
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Cool stories. How long is that bridge going to take? :|
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Mar 12, 2010 23:42
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Mandalay posted:Cool stories. How long is that bridge going to take? :| I'll have a look at the construction progress report on Monday. If I'm remembering correctly, it's about 50% complete. Why, do you live in the area? I've got another project down there (Route 82 over Hungerford Brook) you may want to watch out for. Edit: Or was it Succor Brook? So many little bridges in disrepair these days... Cichlidae fucked around with this message at 03:55 on Mar 13, 2010 |
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Mar 13, 2010 00:48
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Traffic lights have always fascinated ever since watching the time lapse shots of traffic moving in Koyaanisqatsi. I have a question about them: how do they sense a car is needing a left turn and turn change the light promptly to make it a left turn signal? There's no camera on the light as far as I can tell but every time I pull into the left turn lane before the roundabout (lol) near my apartment it changes quickly to a left turn signal and then back again I assume when I'm done turning.
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Mar 13, 2010 09:03
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Peven Stan posted:Traffic lights have always fascinated ever since watching the time lapse shots of traffic moving in Koyaanisqatsi. I have a question about them: how do they sense a car is needing a left turn and turn change the light promptly to make it a left turn signal? There's no camera on the light as far as I can tell but every time I pull into the left turn lane before the roundabout (lol) near my apartment it changes quickly to a left turn signal and then back again I assume when I'm done turning. You'll want to check out this post on detectors. It shows the three most common kinds. Loop detectors are the most common, and can be practically invisible if used properly.
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Mar 13, 2010 18:50
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The official alignment of RI 114 in Pawtucket, RI results in a short stretch of Broadway (a one-way street) carrying both northbound and southbound 114. A highway in a wrong-way multiplex with itself!
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Mar 13, 2010 18:57
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Cichlidae posted:Since the islands are made of concrete, we can't bury the signs in them, or else we'd need to re-pour it every time they're replaced. Instead, we put in PVC sleeves and backfilled with sand. How did that work out? It looks like the signpost is attached to a little piece that is actually in the ground. They can't just concrete in the bottom bit?
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Mar 13, 2010 19:04
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Socket Ryanist posted:The official alignment of RI 114 in Pawtucket, RI results in a short stretch of Broadway (a one-way street) carrying both northbound and southbound 114. Yep, and I've had to drive there several times. Pawtucket is not a place one visits willingly! smackfu posted:It looks like the signpost is attached to a little piece that is actually in the ground. They can't just concrete in the bottom bit? A sign on a splitter island like that will get hit or plowed up yearly. Maintenance much prefers having to dump in a cupful of sand once in a while and have an easily replaceable sign to getting out the jackhammers every time the post gets bent by a plow. The sign's in deeper than it looks, though. That bottom post is probably 3 feet deep, and it's sturdier than it seems. Go out and shake a sign sometime. You can usually make it sway a few inches, but anything more than a foot is very unusual (and probably grounds for replacement).
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Mar 13, 2010 19:08
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Cichlidae posted:
http://www.youtube.com/watch?v=osocGiofdvc
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Mar 14, 2010 03:42
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Cichlidae posted:
I showed this to a friend and he pointed out that the pot seems to be calling the kettle black. Edit: vvv That seems to be a reasonable explanation! Choadmaster fucked around with this message at 03:06 on Mar 15, 2010 |
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Mar 14, 2010 10:42
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Jethro posted:Anyone caught doing this should be sentenced to watching video of the I-35 bridge collapse on repeat for 8 hours. To be fair, it's a pretty small bridge, so I can see why the prospect of crashing through it doesn't seem terribly frightening. A ten-foot drop can still kill you, though, and breaking the bridge would increase the cleanup costs tenfold, further raising the financial burden on the taxpayers. Choadmaster posted:I showed this to a friend and he pointed out that the pot seems to be calling the kettle black. Difference is, I took that shot through the windshield of a car from the passenger seat
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Mar 14, 2010 13:54
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Cichlidae posted:
Where was this sign? Last I checked the button copy using the capital letters for destinations is about the oldest you can get in CT today.
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Mar 15, 2010 03:21
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kefkafloyd posted:Where was this sign? Last I checked the button copy using the capital letters for destinations is about the oldest you can get in CT today. Route 117 NB in Groton, at the I-95 overpass. Some of the oldest signs in the state, though, are on 395. I'll have a project to replace those when I get the money.
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Mar 15, 2010 04:08
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1. Why does connecticut have slow vehicle lanes everywhere on the interstate, instead of just adding a third lane? 2. What goes into designing toll booths? I was on the Jersey turnpike and the GSP and they have some seriously high flow setups there.
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Mar 15, 2010 05:37
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Cichlidae posted:Route 117 NB in Groton, at the I-95 overpass. Some of the oldest signs in the state, though, are on 395. I'll have a project to replace those when I get the money. You should send your old sign pictures to this guy. He'd appreciate them.
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Mar 15, 2010 20:21
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NightGyr posted:1. Why does connecticut have slow vehicle lanes everywhere on the interstate, instead of just adding a third lane? If they're separated by double white skips, they're used as climbing lanes. Not so much on the interstates, though; they're mostly on Routes 2 and 9. Climbing lanes are recommended for any long uphill grades, so trucks can hang out in the right lane and drive slowly while normal traffic passes them. The shoulders adjacent to climbing lanes are generally substandard, so we couldn't stripe them as regular lanes without design exceptions. If you're talking about the auxiliary lanes, especially on I-95, those aren't full travel lanes because they're too short and are primarily used as speed-change lanes between interchanges. quote:2. What goes into designing toll booths? I was on the Jersey turnpike and the GSP and they have some seriously high flow setups there. I've never designed one, since tolls were abolished here in 1988. From what I've read, though, there are a number of interesting ideas to help make them safer. Since I don't have any experience in the matter, you should get the information straight from the horse's mouth. kefkafloyd posted:You should send your old sign pictures to this guy. He'd appreciate them. Done, and I sent him the link to Photolog as well.
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Mar 15, 2010 22:50
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Our city just opened a giant cross-city tunnel. Is it what you would spend 3.2 billion (Australian) dollars on? Any comments on tunnels in general? It's only two lanes the whole way through and apparently one was blocked by a car with a flat tyre the very first morning.
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Mar 17, 2010 04:42
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Kazan posted:Our city just opened a giant cross-city tunnel. Is it what you would spend 3.2 billion (Australian) dollars on? Any comments on tunnels in general? It's only two lanes the whole way through and apparently one was blocked by a car with a flat tyre the very first morning. That looks pretty cool, actually. Construction was incredibly fast: conception to completion in under 10 years. The free month is a good idea, too, because it'll give people a chance to get used to the route and increase ridership. As to how they're going to fit 135,000 cars in a 2-lane tunnel, though... even if it were reversible and served only the peak hourly direction, and conditions were ideal, 2200 pcplph * 2 lanes = 4400 veh/hr would give you about 44,000 ADT. There's no possible way to fit 135,000 cars through a two-lane tunnel. Are there plans to twin the tunnel, or are there sections with more than two lanes? Tunnels in general, by the way, are generally quite expensive, but their prevalence in Europe shows how useful and practical they can be. I don't know why they're so expensive elsewhere; one proposal for a 1/3 mile tunnel here cost nearly as much as your $3.2B tunnel (and that's USD), along with hundreds of millions a year in maintenance. From the photos in the Wiki, it looks like the tunnel has 1.2-meter shoulders on each side, give or take. That should be enough space for a broken-down car to pull over and allow one lane of traffic to go past. Hardly ideal (alternating one-way like that, on a two-way road, can only carry about 750 veh/hr), but not a fatal flaw, either.
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Mar 17, 2010 12:47
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Cichlidae posted:As to how they're going to fit 135,000 cars in a 2-lane tunnel, though... According to the article it's two parallel tubes, with 2 lanes in each. You can just see the other tunnel to the right of this image.
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Mar 17, 2010 13:58
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Still reading this thread but I thought you might like a laugh at some of the terrible intersections I used to have to deal with on the M58, Lancashire, England. The motorway runs SW-NE, starting at the far north of Liverpool at the notorious Switch Island interchange has exactly one junction, serving the town of Skelmersdale, locally known as Skem (the similarity to the word Scum is almost certainly intentional, the place is a poo poo hole, a failed 60s "new town" experiment, kind of like a crap version of Milton Keynes) to the point that some of the motorway road signs actually say Skem to save on a few feet of metal. Finally it ends at the M6 which is pretty much the major north-south route though England and the only sane route to take if you want to visit Scotland. I am certain that the traffic engineers simply designed some junctions to look like diagrams of reproductive organs and somehow they got mixed up with the actual designs and were approved and built. Lets start with J1, the Skelmersdale exit, a ridiculous 3 leaf clover I guess you'd call it.  Click for Google maps The two leaves of the clover make up the balls and the major road heading north is the cock. Not sure what that loop in the south is for, maybe the designer had terminal prostate cancer? I certainly hope so. Aside from that it means that no matter which direction you exit the M58 from, if you're going north you have to make a pointless loop around the south. There's also the usual weaving issues that go with with a cloverleaf. Sure they've separated out that lane but as the clovers are so big, and the M58 is a pretty fast motorway (90mph is not uncommon) there are plenty of idiots who will continue at that sort of speeds. To correct this they've added in a give way line (yield in US speak) to prioritise exiting traffic over joining traffic. But just think of the problems this could cause if a major traffic generator was ever built on that road, traffic for the M58 east could back up around the left testicle, around the big cancerous tumour, around the right testicle and into the weaving area, resulting in gridlock. There's plenty of land around so I'm sure you could fix this one pretty easily. What surprises me is that given that Skem was built from scratch in the 60s, is this seriously the best they could come up with? Lets move a bit further east, to the junction with the M6. Worth noting here is that there is another route from Liverpool to the M6 which joins it a fair bit further south, so the majority of traffic from Liverpool will want to head north, and traffic exiting the M6 onto the M58 will mainly be arriving from the north.  I assume those two roundabouts would be called kidneys, but I'm going to continue the theme from before and call them ovaries instead. Anyway as you can see there is a major conflict point where traffic heading south/west has to cross over traffic heading east/north. Solved in the same way that every lovely roundabout interchange in the UK is solved, by putting traffic lights at various points on the roundabout. Again, land isn't a huge issue here, so I'm sure you can fix this up pretty easily. These are just the warm ups until I present the horror that is Switch Island Unfortunately Google haven't updated their satellite images of this, and their map contains an error too.  If you look at the satellite image you can see that this was originally a huge at-grade roundabout, then they built a dual carriageway through it (and no it's not the A59, if you were heading south on the A59, you'd have to exit and take the roundabout else you'd end up on the A5036. Then the western loop of the roundabout (incorrectly labelled Dunnings Bridge Road, when it's no longer a road) was closed and turned into a truck inspection point, making a half roundabout with the northbound carriageway of the A5036/A59 part of the roundabout now. They've changed it again since I was last there, according to the map, looks like they have built a smaller roundabout inside the bigger half roundabout. I honestly don't know what the gently caress is going on. Most conflict points are, of course, traffic light controlled but there are still plenty of problems. Parts of this junction are 5 or 6 lanes wide (pretty much unheard of in the UK, especially up north) and the signage telling you what lane to be in doesn't reflect what locals who know the road well actually do. The weaving and potential for collisions is terrible. Clearly the solution would be to raze the whole thing to the ground and start again, but it's such an important and heavily congested junction that this simply isn't possible. This is a classic example of road projects being cut back and ruining things. Neither the M57 nor the M58 were originally meant to terminate here. The M57 were to continue northwest to Southport (a minor tourist destination that's nowadays populated entirely by old people) making the A59 northbound pretty much redundant except as a local road and the M58 was to continue to the docks in Bootle (just north of Liverpool). If these roads had ever been completed, the original grade separated roundabout interchange would probably have been fine. And that's the M58, a road with only 3 major junctions and they're all terrible. So, reckon you can fix Switch Island? edit: Wikipedia posted:Switch Island [1][2] is a road junction south of Maghull and near Aintree in Merseyside, England on the Liverpool rural-urban fringe. The junction is at the western terminus of both the M57 and M58 motorways, which converge on the A59 trunk road, the north-south route from Liverpool. The junction is also the terminus of the A5036, a road which serves the Port of Liverpool. It's also worth noting that while the M62 is the main route to the M6 from central Liverpool (this is the one that joins the M6 further south), if there is an accident on the M6 (and there is always an accident on the M6, the question is simply one of where) then it is often quicker to head down the M57 (which intersects with the M62 just a few miles west of Liverpool, on a stupid 3 level stacked roundabout with 7 exits) onto the M58 and then onto the M6. Even though this route is longer and Switch Island is a gigantic clusterfuck, it's still quicker than dealing with the kind of jams that happen on the M6. So you can get a lot of extra traffic here if there is a bad accident. Here is an overview of the area which should make this make more sense. Lum fucked around with this message at 22:21 on Mar 17, 2010 |
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Mar 17, 2010 21:40
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Digital War posted:According to the article it's two parallel tubes, with 2 lanes in each. You can just see the other tunnel to the right of this image. That makes a lot more sense, though I'm still not sure how they're going to fit 135k ADT in four lanes... Lum posted:So, reckon you can fix Switch Island? Thanks for the overview! I've seen that first interchange somewhere before; may have been earlier in the thread. The second is basically a dogbone interchange with the diamond ramps twisted into a parclo, which isn't so bad in theory, but the implementation lacks a certain amount of refinement. As for Switch Island, looking at the aerials on bing maps makes it a bit more obvious what's going on. That sort of design has no place on a motorway. The weaving conflicts are immense, and I'd imagine there are many sideswipes. How to fix it? That's a tricky question. If I had more time, I'd go through the legs and do it properly. For now, I think you could connect the M57 directly to the M58, then use a pair of trumpet interchanges or directional T interchanges and a short connector roadway to connect the A59. It could be done without much disruption to existing traffic patterns, too.
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Mar 17, 2010 22:26
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Here's a fun quiz to see if you guys have been paying attention! I was looking at US 44 over Avon Mountain, which has been under construction for a few years, on the Photolog. I came across a work zone where every single sign was wrong in some way. Some are easier to spot than others, so there's something for everyone! See if you can find what's wrong with these signs.      
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Mar 17, 2010 22:31
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Cichlidae posted:Thanks for the overview! I've seen that first interchange somewhere before; may have been earlier in the thread. The second is basically a dogbone interchange with the diamond ramps twisted into a parclo, which isn't so bad in theory, but the implementation lacks a certain amount of refinement. Given that the predominant traffic flow is east -> north and south -> west, a dogbone seems a bit of a poor choice. I would have thought even a trumpet would flow better, and leave plenty of room to come up with some other way of connecting the local roads. quote:As for Switch Island, looking at the aerials on bing maps makes it a bit more obvious what's going on. That sort of design has no place on a motorway. The weaving conflicts are immense, and I'd imagine there are many sideswipes. How to fix it? That's a tricky question. If I had more time, I'd go through the legs and do it properly. For now, I think you could connect the M57 directly to the M58, then use a pair of trumpet interchanges or directional T interchanges and a short connector roadway to connect the A59. It could be done without much disruption to existing traffic patterns, too. I wish they would connect the M57 directly to the M58. I'm biassed because I used to live in Liverpool South, so mainly used that route to avoid the M6. I'm not sure if that's the most common route though. I'd imagine that the A5036 (which serves Bootle docks) onto both motorways, and vice versa, would be the most common, but that's purely a guess. You are right about the weaving. I've never seen a sideswipe there, but going off my memories of local traffic reports on the radio, accidents were not uncommon. Edit: I'm guessing there is some reason they can't connect the M57 and M58 as there have been at least two rounds of "improvements" to the junction and it hasn't happened. Maybe there's some frogs in that field or something. Edit2: You might have seen that first junction on the CRBD "bad junctions" section. My favourite from there is Great Barr roundabout, where the M6 (notice a theme here?) dumps traffic onto the inside of a roundabout rather than the more traditional outside. And going in the other direction you have to exit from the inside. Lum fucked around with this message at 22:57 on Mar 17, 2010 |
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Mar 17, 2010 22:44
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Digital War posted:According to the article it's two parallel tubes, with 2 lanes in each. You can just see the other tunnel to the right of this image. Thanks, that's right, two lanes in each direction.
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Mar 18, 2010 12:03
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Lum posted:Edit2: You might have seen that first junction on the CRBD "bad junctions" section. My favourite from there is Great Barr roundabout, where the M6 (notice a theme here?) dumps traffic onto the inside of a roundabout rather than the more traditional outside. And going in the other direction you have to exit from the inside. I live near the Great Barr junction (J7 of the M6) and have used it several times. The junction is more fun during the 18 hours of traffic jams that section of the M6 has, especially when people won't move the gently caress over or let you merge I personally don't think the M6 has that many bad junctions. There is one notorious one, though, right at the start of the Motorway at it's junction with the M1 (London to Leeds/Yorkshire) and A14 (Major trunk route to the east coast). It's about here. As you can tell, it's basically a clusterfuck of 3 major routes. The M1 was first built through here in the 60's with the slip roads for the M6 waiting for the road to be extended down to it. Then, during the 90's, the A14 was being built and, because of the lack of any thought into the design of the drat thing, they just plonked down 2 dumbell roundabouts and shoehorned the road into it, leaving the abortion that you see before you! Fortunately, the Highways Agency have noticed how much of an abortion this junction is and are planning to rebuild the junction, with a plan to start as early as autumn next year. Hopefully they will get on to fixing this junction as it is hell at the best of times! Wow! I didn't think I could type so much about roads on a forum that has nothing to do with roads!
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Mar 18, 2010 12:15
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Just thought of a slightly different game. Here's my idea of how I'd fix the M6/M58 junction  Since this is SA and you don't have to be nice to the general public here, tell me why I'm wrong! Personally I think it's alright as it reuses a fair few bits of road and the UK government do like to do jobs on the cheap, and it makes the entire junction free flowing, eliminating both roundabouts. The bridge here was originally built with the intention that the M58 would continue west under it, so there should be room for my additional lane. Obviously the curves would be smoother. I'm on a laptop with a touchpad so can't really do freehand curves. Also a couple more questions about your job. In my experience in the public sector, everyone has to be incredibly guarded in their speech and incredibly politically correct. This being SA you don't have to and you can freely complain about "Granny McGee" without repercussions. Given that old people seem to be a regular cause of complications in your work, whether it's due to their slow driving, slow crossing of roads or having the time to complain about stupid things, can you get away with calling them horrible names ("coffin dodgers" is a popular one on UK motoring forums) when it's just your management and co-workers around or do you have to use terms like "senior citizens" and generally pretend that they aren't a burden and a massive pain in the arse. Secondly, how has the introduction of satnav affected your work. It must be really frustrating when you build a new road and everyone with out of date maps still goes through the own centre or whatever bottleneck you have just bypassed. Where I live we have a different problem. Foreign truck drivers with cheap nasty satnavs such as TomToms which arent designed for truckers. Google maps makes the same mistake, look at the route it's chosen here for Newbridge to Wattsville.  Looks simple enough right, except that road is mostly single track and over a very steep hill. The two major roads to the east and west both go through the valleys to remain mostly flat. Note that there is no google street view available as presumably the google car didn't fancy driving up there. So instead I had to use GIS...  .This is the road that both Google and the TomToms want to send you down, rather than the A roads. Truckers end up taking them and then getting wedged between two houses and other stupidity. The problem is that satnavs assume that the speed limit reflects the design speed of the roads. That route is entirely a 60mph limit, yes even the single track bits. This is a throwback to the early days of speed limits in the UK where "built up" areas were automatically 30 limits and everywhere else was "derestricted" ie. no speed limit, use your own judgement. In the 70s the "derestricted" sign was changed to mean "70 if it's a dual carriageway, otherwise 60*" so these roads became a 60 limit. Roads generally got lowered for various reasons such as accident and the wailings of the think of the children brigade (IMO nothing is worse for sensible road design than the outbursts of a grieving mother) so these insignificant tiny little roads just got left alone. ( * - lower limits apply to vehicles larger than cars ) The solution used here is to invent a new sign, that looks a bit like this (only he bottom plate should actually be bolted to the pole)  Unfortunately the picture on the sign is confusing, our version doesn't have the "no trucks" symbol as they don't want tourists in cars up there either, and the wording simply states "Ignore satellite navigation" in both English and Welsh when really it needs to be in Polish, Romanian, Lithuanian, Czech, Spanish and Dutch before it would be useful to stop trucks going up there. Lastly, I note from your OP and various posts in the thread, you seem to be a fan of roundabout interchanges, and I'm not sure why. In the UK these things are amazingly common and seem to be the default design of an unimaginative traffic engineer (typically in the form of a 3 level stacked roundabout) and they're usually terrible. They flow badly, introduce points of conflict and usually end up with bypass lanes getting built and traffic lights on every entrance in a desperate attempt to improve capacity. Here is a particularly horrible one I have to deal with regularly. Click. Note that the picture must have been taken on a Sunday morning or something because at peak times it backs up onto the A470 westbound and onto the M4 in both directions. It probably also backs up onto the A470 in the other direction too but I wouldn't know as I avoid Cardiff like the plague. Of course each conflict point is signal controlled and the weaving is immense as locals weave just because they know which lanes are slow in each section and non-locals get utterly confused and lost on the whole thing. It's not unknown for me to come off the M470 eastbound intending to take the M4 westbound and spend about 10 minutes on this roundabout. e: It also makes you wonder at what point a roundabout becomes so big it becomes a one way system. That is what my satnav identifies it as. Could this be a way to sneak roundabouts into the American system by starting big and making them smaller over the next 50 years? Lum fucked around with this message at 12:54 on Mar 18, 2010 |
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Mar 18, 2010 12:17
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Lum posted:Just thought of a slightly different game. That's quite good, actually, but there are some problems. First off, there's no way to get to that little road in the northeast from the motorway. Assuming each of those yellow ramps you drew are one-way, that is. If you want to make some two-way, things get much trickier. Also, with your design, fitting in the overpass to the east of the motorway might be a little tricky with the available land. I'm not sure there'd be sufficient room to grade your yellow ramp up/down 20 feet. Personally, I'd give serious thought to just replacing both roundabouts with signalized intersections. I don't know what the volumes are, but if they're using a roundabout today, they could probably work with a signal. Then again, this is a motorway-motorway junction, and that could violate driver expectancy. How about eliminating your yellow ramps altogether and just using the blue ones? Depending on the volumes and local business, as well as the distance to the next interchange, that might be a better idea. Lum posted:Also a couple more questions about your job. Yes, exactly. Not only can I not offend anyone or step on any toes, but nearly everything I do is completely open to the public. Any emails I send or notes I write can, at any point, be viewed by any citizen. I think we're even supposed to CC the state archives in every email, but nobody does that yet, thank goodness. Can you imagine? So, we can still make fun of people we dislike, as long as we do it verbally, very quietly, and only around people we trust. Or on Something Awful on our free time. Lum posted:Lastly, I note from your OP and various posts in the thread, you seem to be a fan of roundabout interchanges, and I'm not sure why. In the UK these things are amazingly common and seem to be the default design of an unimaginative traffic engineer (typically in the form of a 3 level stacked roundabout) and they're usually terrible. They flow badly, introduce points of conflict and usually end up with bypass lanes getting built and traffic lights on every entrance in a desperate attempt to improve capacity. I'm a fan of their looks, not their operation. I just think they're very elegant. Obviously they introduce a lot of weaving. Heck, we have some over here, too, and they almost universally work terribly. I know on a couple of occasions, I've said, "This won't work, but it looks so pretty I couldn't resist..." One more thing: keep in mind that "roundabout" has a different meaning here in the States. When I say roundabout interchange, I also use it to refer to a dogbone interchange, for example, or any diamond or parclo that uses a roundabout instead of a signal/stop sign. It's really unfortunate that there's no international standard for road nomenclature, but, then again, there are so few people who really care, and engineers much prefer plans to words on a page. Edit: Ah, you added more to your post! I can't see your picture of the sign, unfortunately. Lum posted:Secondly, how has the introduction of satnav affected your work. It must be really frustrating when you build a new road and everyone with out of date maps still goes through the own centre or whatever bottleneck you have just bypassed. As someone who works with maps on a daily basis, let me first say that Google especially has a LOT of errors. Some of the roads it shows haven't existed for 30+ years. Many have their names or designations wrong. Other mapping services have similar issues. Bad routing, as you noted, is another big issue. Hopefully, it's something that the inexorable march of progress will stamp out, but the lack of an up-to-date mapping program will always be a problem without rapid, direct coordination between the people that build and maintain the roads and the map makers. It's only a matter of time before your GPS will be able to tell which lane you're in, and if it keeps telling you to get left when the left lane is currently a ditch, well, that's a problem! I believe there is one person in the DOT who works with map companies, but it's not a constant "traffic's going to be shifted to the right for 6 hours today on this 300-meter stretch" thing. Even if it were, I doubt TomTom would want to update their maps hourly. I don't know if it would even be feasible to do that in the future, as everything is so self-censored here that we'd need to issue full press releases with a page-long CC list for each one. Another Edit: Big traffic circles are what's gotten so much negative publicity over the years. There's not much public outcry against modern roundabouts, so we start with those and plan to make them bigger if we run out of capacity! 
Cichlidae fucked around with this message at 22:38 on Mar 18, 2010 |
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Mar 18, 2010 12:44
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Cichlidae posted:Here's a fun quiz to see if you guys have been paying attention! I was looking at US 44 over Avon Mountain, which has been under construction for a few years, on the Photolog. I came across a work zone where every single sign was wrong in some way. Some are easier to spot than others, so there's something for everyone! See if you can find what's wrong with these signs. Hmmm let's see... 1) Not sure, but given that I've never seen a sign with that text maybe it's just non-standard wording. Usually merge signs tell you left/right. 2) I don't know if patching signs like that is appropriate, but they seem to have done it poorly here. Instead of putting "left" over the original sign they put a giant left arrow. And then put "left" on that arrow, in case you couldn't tell which way it was pointing.  3) I just don't see the point of this one, you're clearly already at one lane by this point so it's kinda pointless instructing drivers to merge here. If they haven't merged by now then they're in the oncoming traffic lane. 4) Did they just slap white-out on a sign? 5) It fell  6) I thought you weren't supposed to combine different sign colors/types on one base. And what's that yellow one on top of the normal street marker? 7) That's not a sign, that is a crane. A crane that would freak me out if I had to drive that close to it.
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Mar 18, 2010 13:12
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The problem of GPS navigation is really interesting. As a road designer / traffic engineer, you ideally design the entire road system to be the most efficient at everyone around, in some averaged sense. You also design the roads to avoid loud, fast traffic down residential streets, limit the speed to satisfy the wailing mother brigade, etc. On the other hand, I as a commuter with a GPS unit have a completely different goal: get me to where I'm going, as fast as possible, regardless of global efficiency or the inconvenience to other commuters or residents. As Braess's paradox shows, this may be entirely at odds with what the traffic engineers want. If I had some sort of constantly-updated GPS unit that actually took into account instantaneous traffic conditions on the roads (fake edit: You can already get this), and a large portion of people were using them, would that even be a stable system? Imagine two parallel roads where one is busy and the other isn't. The GPS units would send everyone to the not-busy road, then realize that it's busy and send everyone back, etc. I remember reading an article (I think in Wired?) about this problem. The makers of this system in California that takes traffic data from all kinds of sources and sends it to their users' cars was wrestling with the ethics of sending some people on a less-optimal route in order to optimize the system. But each user is paying the company to tell them the fastest possible route for them personally. Very thought-provoking.
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Mar 18, 2010 13:42
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Cichlidae posted:That's quite good, actually, but there are some problems. First off, there's no way to get to that little road in the northeast from the motorway. Assuming each of those yellow ramps you drew are one-way, that is. If you want to make some two-way, things get much trickier. Doh! How often mistakes like that go through unnoticed until late in the design stage, or after building has started. quote:Also, with your design, fitting in the overpass to the east of the motorway might be a little tricky with the available land. I'm not sure there'd be sufficient room to grade your yellow ramp up/down 20 feet. The existing offramp would have to be turned into the raised section for this to work. I can see how actually building that would cause massive problems though. Similar would have to happen with the yellow ramp. Hows about this version?  Edit: Actually, here's a better design. Ignore the yellow roads. I didn't keep the layers saved. Just the red and blue ones count.  The biggest problem that I can see is the weaving on the M6 southbound that would be introduced, so maybe add it in addition to the onramp from my earlier version, and use the onramp from the diamond only for access to the M58. quote:Personally, I'd give serious thought to just replacing both roundabouts with signalized intersections. I don't know what the volumes are, but if they're using a roundabout today, they could probably work with a signal. Then again, this is a motorway-motorway junction, and that could violate driver expectancy. That could work well. I'm a fan fo free flowing junctions though, especially when it's motorway-motorway. quote:How about eliminating your yellow ramps altogether and just using the blue ones? Depending on the volumes and local business, as well as the distance to the next interchange, that might be a better idea. That would be a lot easier. I suspect local residents would bitch and moan and get it blocked though. quote:Yes, exactly. Not only can I not offend anyone or step on any toes, but nearly everything I do is completely open to the public. Any emails I send or notes I write can, at any point, be viewed by any citizen. I think we're even supposed to CC the state archives in every email, but nobody does that yet, thank goodness. Can you imagine? As an IT worker I can tell you that whoever told you to do that is an idiot. It's trivial to set up most mail servers to automatically copy and archive every email that passes through it. Expecting the end users to remember to do that every time is just retarded. So, we can still make fun of people we dislike, as long as we do it verbally, very quietly, and only around people we trust. Or on Something Awful on our free time. I'm a fan of their looks, not their operation. I just think they're very elegant. Obviously they introduce a lot of weaving. Heck, we have some over here, too, and they almost universally work terribly. I know on a couple of occasions, I've said, "This won't work, but it looks so pretty I couldn't resist..." One more thing: keep in mind that "roundabout" has a different meaning here in the States. When I say roundabout interchange, I also use it to refer to a dogbone interchange[/quote] And there's two types of dogbone too. There's the kind with two roundabouts joined together by a small stretch of road or dual carriageway, and there's the kind where they take that design and then lop out the section in the middle turning the entire thing into one giant strangely shaped roundabout. I usually call them "boneabouts" quote:Edit: Ah, you added more to your post! I can't see your picture of the sign, unfortunately. Lum fucked around with this message at 14:16 on Mar 18, 2010 |
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Mar 18, 2010 14:03
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MyFaceBeHi posted:I live near the Great Barr junction (J7 of the M6) and have used it several times. The junction is more fun during the 18 hours of traffic jams that section of the M6 has, especially when people won't move the gently caress over or let you merge Oh god I hate that junction so much. The A14 was basically cobbled together on the cheap by reusing random bits of other roads and creating that lovely junction at the end. At peak times, the M1 backs up for a mile or two on the inside lane (you forgot to mention that the dumbbell/dogbone is signal controlled too) and then backs up down the middle lane too. This is because while L1 is the single exit lane for this junction, the offramp is actually two lanes, so the middle fills up with chancers trying to barge in to L2 of the offramp. This leaves only one lane of the M1 left for southbound traffic trying to get to London. For non-UK people. This junction connects the two major north-south routes in the UK, the M6 (serving North-West england and the entirety of Scotland) to the M1 (serving North-East England) and then continues as the M1, southbound to London. The A14 is also a pretty important road as it connects to Cambridge. You might have heard of Cambridge University which is one of the two most prestigious universities in the country. Anyway, lovely M6 junctions. There's this one, Great Barr, the clusterfuck that is the M6/M42/M6Toll junction, spaghetti junction, The M6/M5 junction which is woefully underspecced and too close to J9 causing weaving, the M6/M62 junction which is massively underspecced and also so close to the Thelwall viaduct that tailbacks due to crawling trucks quickly back up this junction onto the M62 in both directions. A pity really, because from the air it looks perfect, elegant and free flowing. quote:Fortunately, the Highways Agency have noticed how much of an abortion this junction is and are planning to rebuild the junction, with a plan to start as early as autumn next year. Hopefully they will get on to fixing this junction as it is hell at the best of times! I don't know whether to cheer because it's getting fixed, or cry because this means 2 years of roadworks, surely. I mean sure, there's always roadworks on the M6, but putting them here is just going to be hell, it would probably be quicker to go M5/M42/M40 and then A43 or M25. Lum fucked around with this message at 14:36 on Mar 18, 2010 |
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Mar 18, 2010 14:34
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Lum posted:Anyway, lovely M6 junctions. There's this one, Great Barr, the clusterfuck that is the M6/M42/M6Toll junction, spaghetti junction, The M6/M5 junction which is woefully underspecced and too close to J9 causing weaving, the M6/M62 junction which is massively underspecced and also so close to the Thelwall viaduct that tailbacks due to crawling trucks quickly back up this junction onto the M62 in both directions. A pity really, because from the air it looks perfect, elegant and free flowing. The M6/6Toll/42 junctions is just a bodge job, and a horrible bodge job at that. It also means that the M42 becomes the size of an american urban freeway for ~3 miles whilst everyone fights it out to get in any lane possible! Spaghetti is a brilliant junction outside of rush hour! Unfortunately, most of the traffic is generally going from A38(M) to M6 West, which results in many an accident/traffic jam. Besides that it's a brilliant junction and if any amendment is made to it I will go down there and beat people up! The M6/M5 junction is an rear end in a top hat with the gridlock that inevitably happens every single day (yes, including Sundays!). The best thing to do with that junction is (besides knocking down J9 because who goes to Wednesbury?) building collecter/distributor roads and widdening it. Unfortunatly they went down the cheap rear end route of the stupid I could go on but then I'd be ranting!
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Mar 18, 2010 15:09
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