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JackBoCracken posted:How do they decide which landmarks get their own freeway sign? It's much more of a political process than an engineering decision. If a state senator calls me up and says he wants a freeway sign for a museum in his town, I pretty much have to say "yes." This leads to a preponderance of unwarranted signs on our highways. You might have noticed signs on highways that say "Korean War Veterans Memorial Highway" or similar. Those are actually discouraged in the MUTCD. Memorial signs should be very small, not legible from the road, and placed at turn-outs so people can stop to read them if they REALLY want. Politicians want to be able to say, "See that sign on the freeway? That means I care about you, war veteran/police officer/elderly person! Vote for me!" Engineering judgment be damned.
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Aug 8, 2009 21:51
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Simkin posted:I think you briefly mentioned this earlier in the thread, but do you occasionally fire up SC4 just to torment sims with insane traffic extravagancies? The person running the current LP seems to be having a bit of fun with NAM, but I imagine that you could make the program really hum (or grind to a hilariously orchestrated halt NAM's pretty interesting, but not very easy to use. I have to lay down the freeways before building anything else, or it all ends up getting bulldozed. Even then, my interchanges end up much bigger than the stock ones. I love the slope mod, the custom interchanges, and the pedestrian malls, though. Here's what I've built so far, all of this is under a week old: 
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Aug 8, 2009 22:00
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Are the guys over at Surveys and ROW your favorite people? Do you work in Newington?
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Aug 8, 2009 22:25
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ease posted:Are the guys over at Surveys and ROW your favorite people? Do you work in Newington? I've actually never met the surveyors. As for ROW, they have a pretty funny sense of humor. I really haven't worked closely with either one. Why, do you know someone down there? I'd rather not get too specific about where I work, if you don't mind. This thread is pretty high in the google rankings already and my coworkers might catch on!
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Aug 8, 2009 22:41
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I'm a surveyor for an engineering firm, so I visit the ROW/Surveyors all the time in my district. I feel sorry because they have no money for new equipment. They all seem to love their jobs tho.
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Aug 8, 2009 22:43
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ease posted:I'm a surveyor for an engineering firm, so I visit the ROW/Surveyors all the time in my district. I feel sorry because they have no money for new equipment. They all seem to love their jobs tho. We have no money for anything. The governor canceled preventative maintenance on our printers, so half the printers are broken, people are sending office-wide emails looking for toner, we're hoarding paper like it's gold... they can't even afford pencils for us. There's no way we're getting new equipment.
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Aug 8, 2009 23:20
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Cichlidae posted:We have no money for anything. The governor canceled preventative maintenance on our printers, so half the printers are broken, people are sending office-wide emails looking for toner, we're hoarding paper like it's gold... they can't even afford pencils for us. There's no way we're getting new equipment. "Sir, we need to make some budget cuts. I recommend cutting down on extraneous spending in--" "Stop giving money to the engineers." "Sir?" "I'm sure they only spend it on booze and women anyway."
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Aug 8, 2009 23:54
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Der Metzgermeister posted:"Sir, we need to make some budget cuts. I recommend cutting down on extraneous spending in--" Well, if you look at how we spent money back in the 70s, that's what you'd see. It wasn't unusual to hold official meetings at strip clubs or bars. Some aspects of that have carried over, though! For Rhode Island's biggest construction project, the relocation of I-195 in Providence, the construction office was built on the second floor of a strip club. Things like that keep our bad reputation going. There's so much public hatred toward the DOT, and everything our contractors or consultants do wrong gets blamed on us. It's a vicious cycle; I can't tell people I meet where I work, or I'd get yelled at. Cichlidae fucked around with this message at 01:35 on Aug 9, 2009 |
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Aug 9, 2009 01:22
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So do you and your work buddies love this traffic flash game or what?: http://www.kongregate.com/games/ArmorGames/i-love-traffic Also, I've always really wanted to know how people make road signs, especially the ones like the yellow curve warnings that are sometimes quite specific to the road in question. Is there just a press in the back room or what? Lastly, what does it mean when something is a DOT paint testing area? When I was young I imagined they were coming up with all sorts of new ways to direct traffic and warn drivers, which was why that road had such a bad accident rate. When I got older I realized it was probably more about how well the paint holds up to traffic. But on a recent trip I saw a testing area out in the middle of nowhere (Eastern Oregon high desert to be exact). What's up?
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Aug 9, 2009 02:51
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Kaal posted:So do you and your work buddies love this traffic flash game or what?: http://www.kongregate.com/games/ArmorGames/i-love-traffic Flash is blocked on the work computers, otherwise I could see this happening! quote:Also, I've always really wanted to know how people make road signs, especially the ones like the yellow curve warnings that are sometimes quite specific to the road in question. Is there just a press in the back room or what? The sign shop is a magical place. They get in aluminum blanks, which are pre-cut sheets of metal in the shape of a sign. For bigger signs, there's a giant roll of aluminum (imagine foil, but scaled up by about 40 times in every dimension) and a big machine to cut it. The sign blanks get washed off carefully, then we stick a retroreflective background layer to it. Next, there's a CNC machine that takes computer files and cuts them into big sheets of colored vinyl. We stick a big sheet of transfer tape to the vinyl and lift it off, then stick that to the sign. The tape holds the vinyl to the backing, and the sign is ready to go. For very small signs, we have a silkscreen studio. It's great for making a lot of little signs in a very short time. For huge signs, they're made with extruded aluminum, which is bolted together. The characters on the front of extruded signs are a foot or two high, and are riveted to the sign, along with some reflective buttons to help them stay visible at night. quote:Lastly, what does it mean when something is a DOT paint testing area? When I was young I imagined they were coming up with all sorts of new ways to direct traffic and warn drivers, which was why that road had such a bad accident rate. When I got older I realized it was probably more about how well the paint holds up to traffic. But on a recent trip I saw a testing area out in the middle of nowhere (Eastern Oregon high desert to be exact). What's up? We're always experimenting with new techniques and new materials. Using the scientific method, we need to test them under a variety of controlled circumstances. We set aside a mile or so of road, use the new technique, and wait a few years. The data collected at that point (remaining reflectivity, number of accidents, overall quality are a few we might use for paint) is compared to the nearby stretches of road, which act as a control. The busiest area isn't always the best place to test something. Often, it's somewhere with difficult weather conditions, or a very steady/predictable traffic flow. Our test area in CT is generally along a pretty rural stretch of highway, too.
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Aug 9, 2009 03:09
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Awesome! I've been wondering about all that for years!
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Aug 9, 2009 03:22
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Soap Scum posted:What's your opinion of the fused grid as a form of urban design? (That wikipedia page is awful. I bet someone copied it out of a planning book.)
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Aug 10, 2009 15:18
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Really great an informative thread so far. I'm wondering if there is a possible way to fix this area of the town I live in. There are a lot of terribly wrong traffic things in this town but this area is the worst clusterfuck. http://maps.google.com/maps?f=q&sou...006899&t=k&z=17 Weaving getting on and off the freeway, weaving on the bridge, and the rail tracks there to gently caress everything up (all traffic into downtown must come through a tight tunnel under the tracks). The cars in the satellite image show how backed up the road gets on a normal day, and there really is no alternate route to cross the tracks. The cloverleaf getting onto the freeway going SW is really brutal, you have people going 20-25 mph around that curve and then about 200 feet to accelerate to freeway speed. Most people make it to about 40-50 mph when there are trucks going 60-65 in that lane. You also have the other people getting off the freeway weaving in. Another issue is that of people merging over into the bike lane & diagonal white lines going west on the bridge because at the last minute they realize they are in a freeway lane. I have seen lots of people have "oh poo poo" moments on that bridge onramp and more than a few accidents there. Edit: whats up 3 leaf clover?
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Aug 10, 2009 16:51
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smackfu posted:Is fused grid what they have in Phoenix? Somewhat similar, though Phoenix is more geared toward vehicular traffic. In a fused grid, the areas inside the big blocks would have winding streets with lots of dead ends. In Phoenix, for the most part, it's just narrower streets that run parallel to the main roads. There are some exceptions; I don't think the city cares too much how developers run their subdivisions. A fused grid emphasizes pedestrian traffic; because of the labyrinthine road layout, it's easier to traverse the neighborhood on foot than in a car. Allowing for pedestrian traffic in Phoenix, though, seems rather futile. I've walked there in the summertime, and I wouldn't want to go any farther than a quarter mile. Maybe that's just because I'm a snowbird, though. To each his own. Edit: to emphasize the concept, here is a picture:  Phoenix's layout doesn't discourage cars from cutting through neighborhoods, nor does it make walking easier than driving. Cichlidae fucked around with this message at 17:29 on Aug 10, 2009 |
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Aug 10, 2009 17:16
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Jumo posted:Really great an informative thread so far. I'm wondering if there is a possible way to fix this area of the town I live in. There are a lot of terribly wrong traffic things in this town but this area is the worst clusterfuck. Yeah, we have that same rail bottleneck here. In a few places, we have 1-lane rail tunnels built in the 1800s, so traffic on an major street has to do alternating one-way traffic... forever. Fixing up railroad problems is a very difficult proposition, because it takes so much to work on an active rail line. quote:The cloverleaf getting onto the freeway going SW is really brutal, you have people going 20-25 mph around that curve and then about 200 feet to accelerate to freeway speed. Most people make it to about 40-50 mph when there are trucks going 60-65 in that lane. You also have the other people getting off the freeway weaving in. It's not as bad as it could be, fortunately, because there's a decent recovery area for if you don't make the merge in time. Still, like all cloverleafs, it's a potentially dangerous situation. quote:Another issue is that of people merging over into the bike lane & diagonal white lines going west on the bridge because at the last minute they realize they are in a freeway lane. I have seen lots of people have "oh poo poo" moments on that bridge onramp and more than a few accidents there. Oh wow, bike lane, too? If I had my way, I'd stick it onto a separate structure. Sticking a bike lane in the middle of weaving traffic doesn't seem like the safest way to do business. I'm on break and can't draw it quickly, but imagine deleting the top left two ramps of that cloverleaf, and creating a signalized intersection where the bottom left ramps come in. That'd fix the weaving issues and prevent people from having to weave across the bike lane, as well as give people coming from 80 a chance to get in the correct lane before the intersection to the west.
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Aug 10, 2009 17:36
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Know anything about signals that give priority to buses/trolleys/etc? I've always thought those were really cool, but I have no idea how they actually work. Another thing I'm curious about is pedestrian signals. Why is it that, at some intersections, there's one all-red-light phase which is the only time the "WALK" sign comes on, and at other intersections, pedestrians crossing each street get separate walk signals when their respective streets have a red. On the one hand, it seems safer to wait for all reds, but on the other hand, that type of signal means you have to wait way longer to get a WALK, so everybody ends up ignoring the sign and crossing whenever they feel like it. (Of course, I live in Massachusetts so it's kind of a moot point, as everyone ignores Don't Walk lights anyway)
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Aug 10, 2009 17:44
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Echo 3 posted:Know anything about signals that give priority to buses/trolleys/etc? I've always thought those were really cool, but I have no idea how they actually work. That's another kind of pre-emption. To oversimplify things to the point of inanity, it's possible to give a bus driver a little button that will turn lights green. I've often been tempted to buy one for my own car, but that would be irresponsible! The point of doing this is that buses typically carry much more people than cars, so it's worth cutting their commutes by several seconds, even if it means inconveniencing other traffic. quote:Another thing I'm curious about is pedestrian signals. Why is it that, at some intersections, there's one all-red-light phase which is the only time the "WALK" sign comes on, and at other intersections, pedestrians crossing each street get separate walk signals when their respective streets have a red. On the one hand, it seems safer to wait for all reds, but on the other hand, that type of signal means you have to wait way longer to get a WALK, so everybody ends up ignoring the sign and crossing whenever they feel like it. It depends on the pedestrian volume. Where there are almost no peds or no sidewalks, we assume they'll cross the side street independently, and provide a button to call the side street phase (but for longer than normal) if they need to cross the main street. Alternating ped phases, we don't do so often, but it's a similar concept with two buttons. It can be confusing if you don't know which one to press! And a dedicated ped phase is used in downtown areas and anywhere else there's a lot of ped traffic. It also eats up a lot of green time. Fun fact: if pedestrians are allowed to cross diagonally, this is known as a scramble crosswalk.
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Aug 10, 2009 17:51
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Cichlidae posted:Oh wow, bike lane, too? If I had my way, I'd stick it onto a separate structure. Sticking a bike lane in the middle of weaving traffic doesn't seem like the safest way to do business. I'm on break and can't draw it quickly, but imagine deleting the top left two ramps of that cloverleaf, and creating a signalized intersection where the bottom left ramps come in. That'd fix the weaving issues and prevent people from having to weave across the bike lane, as well as give people coming from 80 a chance to get in the correct lane before the intersection to the west. I rarely see this bike lane being used, as most people avoid it because it is an insane street. Fortunately there is an alternate route for bikes nearby. Davis has such a nice bike infrastructure it is nearly always faster to go somewhere by bike than car. The Sacramento causeway is another fun bottleneck in my area, and one that probably wont How do you feel about America's tendency to build entire cities based on a gas station that was put there 70 years ago? Is our road-centric culture ever going to bite us in the rear end? Can we please get some urban planners that know how to build public space worth giving a gently caress about? Seems like in Europe they do this rather well.
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Aug 10, 2009 18:37
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Cichlidae posted:And a dedicated ped phase is used in downtown areas and anywhere else there's a lot of ped traffic. It also eats up a lot of green time. Fun fact: if pedestrians are allowed to cross diagonally, this is known as a scramble crosswalk. http://maps.google.com/maps?hl=en&c...=12,115.52,,0,5 At least in my town, the intersection that does this has no regular walk phases, but if you press the button, it inserts one after the next yellow. Which is much better, but only works if you don't have regular pedestrian traffic.
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Aug 10, 2009 18:40
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Jumo posted:I rarely see this bike lane being used, as most people avoid it because it is an insane street. Fortunately there is an alternate route for bikes nearby. Davis has such a nice bike infrastructure it is nearly always faster to go somewhere by bike than car. I was bored at work, so here's a better representation of what you could fix for minimal cost. I added another exit, because if congestion is as bad as you say, it couldn't hurt.  quote:The Sacramento causeway is another fun bottleneck in my area, and one that probably wont It's already biting us in the rear end. Europe was very lucky, because of how the countries there grew up: large urban centers surrounded by farmland. That sort of growth pattern is pretty much ideal for mass transit, since the population is concentrated in such a small area. The farmland is cheap to buy up for the installation of new roads or high-speed train lines. Our country is already getting hosed up the rear end because of our lack of foresight. Congestion alone wastes a TREMENDOUS amount of money every day. I'm talking billions and billions of dollars! Urban planners have noticed that there's no way to "out-grow" congestion; adding more capacity will just result in more demand. The gas shocks recently have reminded us in a very direct way of the dangers of reliance on automobiles. Where does it go from here? Some people think we'll switch over to electric cars, maybe biodiesel, and the price of oil won't be an issue. That means we get to keep our suburbs, our long commutes, our American way of life. I, however, don't want this to happen. Among American traffic engineers, I'm probably in the minority, but I want us to consolidate and use more efficient forms of transportation. Yes, it sucks to trade in your big backyard for an apartment in the city. Yes, the bus is inconvenient, and the guy sitting next to you smells like manure. We'd all have to make major sacrifices in the name of social efficiency.
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Aug 10, 2009 21:53
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smackfu posted:These have one of these in New Haven at Elm and College and it takes *forever* to get the 4-way walk light. And since it's college kids, no one waits, which defeats the point of the signal. Also, it's a fairly blind right turn, so it's not a safe intersection. Ped phases DO seem to take forever! Want to hazard a guess as to why that may be? You're right, it's OLD PEOPLE again! A walk phase has two parts: walk, and flashing don't walk (FDW). The walk time depends on how many people we expect to cross. 5 seconds is usually fine. FDW, however, really sucks. It's the time it takes the oldest, slowest, most arthritic person to cross the widest approach to the street. GrannyMcGee got a brand new walker and she wants to toddle across the intersection at 1.5 mph? We've got her back! Rad Coolkid can make that same crossing in 1/4 the time? Tough poo poo, you've got to wait the full time anyway.
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Aug 10, 2009 21:57
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Cichlidae posted:Where does it go from here? Some people think we'll switch over to electric cars, maybe biodiesel, and the price of oil won't be an issue. That means we get to keep our suburbs, our long commutes, our American way of life. I, however, don't want this to happen. Among American traffic engineers, I'm probably in the minority, but I want us to consolidate and use more efficient forms of transportation. Yes, it sucks to trade in your big backyard for an apartment in the city. Yes, the bus is inconvenient, and the guy sitting next to you smells like manure. We'd all have to make major sacrifices in the name of social efficiency. I feel the same way and there are growing numbers of us. I've lived abroad in a major city where having a car was a liability. It is painfully easy to live without a car 99% of the time there. A decent sized grocery store is only a few blocks away. Subway stops are easily accessible. Buses are even more accessible. Even taxis are usually reasonably priced if you've got bigger things to transport. I bought a computer desk from someone on the other side of the city and just disassembled and brought it back home in a taxi for about $10. There will always be enough work for engineers even if traffic was halved tomorrow.
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Aug 10, 2009 22:11
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Neutrino posted:I feel the same way and there are growing numbers of us. I've lived abroad in a major city where having a car was a liability. It is painfully easy to live without a car 99% of the time there. A decent sized grocery store is only a few blocks away. Subway stops are easily accessible. Buses are even more accessible. Even taxis are usually reasonably priced if you've got bigger things to transport. I bought a computer desk from someone on the other side of the city and just disassembled and brought it back home in a taxi for about $10. It's good to see others have had the same experiences. I'm not kidding when I say that some of my coworkers have never once ridden on a bus or taken a train. And I agree totally, there's plenty of work. Our generation is going to have a very hard time, with the combination of our crumbling infrastructure, a major paradigm shift in transportation, and ever-rising traffic volumes. I'm just lucky I don't have to make the difficult decisions yet: busway or freeway? Trolley or subway? Everything I do involves improving safety, and safety never goes out of style.
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Aug 10, 2009 22:25
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Jumo posted:How do you feel about America's tendency to build entire cities based on a gas station that was put there 70 years ago? Is our road-centric culture ever going to bite us in the rear end? Can we please get some urban planners that know how to build public space worth giving a gently caress about? Seems like in Europe they do this rather well. Unfortunately a denser and more consolidated urban landscape requires much more coordinated and centralized zoning and planning, which sets off the "big gubmint"-alarm in a certain set of people. Hence we'll still have to wait a while for a major paradigm change as far as zoning goes.
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Aug 10, 2009 23:13
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Nesnej posted:The low population density of American cities is definitely a contributing factor, because the upkeep of public spaces costs at certain amount of money, which is sort of wasted if there aren't very many people around to enjoy the place. Just imagine if we did what Germany's doing and prohibited anything dirtier than a compact car from entering smog-choked downtown areas! There would be riots. Riots, blood, and traffic engineers lying dead in the streets.  No drat commie in Warshintin's gonna tell me whur ah can n' can't drav mah Ford!
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Aug 10, 2009 23:29
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This is a really awesome thread. After reading the first page, I fired up Google Earth to have a look at the last three motorway interchanges I've driven through. Strangely enough, you used two of them as your examples on page 2 (M25-M40 and M25-M4 in the UK). Any reason why you chose those ones, out of interest? My third was the M4-M5, which I now know is a stack, with all the roads piled on top of each other in a huge 4-layer sandwich. I'd have called it an iron cross, personally   In Oxford recently one of the big roundabouts was re-done - the new version, which is traffic light controlled, is called "The Hamburger". I think it's improved traffic quite a bit, particularly the main flow which is from the right of the picture to the top left. Any thoughts on the design? 
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Aug 11, 2009 00:19
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10987 posted:This is a really awesome thread. After reading the first page, I fired up Google Earth to have a look at the last three motorway interchanges I've driven through. Strangely enough, you used two of them as your examples on page 2 (M25-M40 and M25-M4 in the UK). Any reason why you chose those ones, out of interest? My third was the M4-M5, which I now know is a stack, with all the roads piled on top of each other in a huge 4-layer sandwich. I'd have called it an iron cross, personally Just really good luck! England has a lot of interchange diversity, and I didn't want to focus entirely on American interchanges. This thread is international, after all. quote:In Oxford recently one of the big roundabouts was re-done - the new version, which is traffic light controlled, is called "The Hamburger". I think it's improved traffic quite a bit, particularly the main flow which is from the right of the picture to the top left. Any thoughts on the design? These are known as "hamburger roundabouts", like you said, or "throughabouts." I've driven through some of those, though they were in much more rural situations, where a major arterial cut through the middle. The concept is still the same, though: the major movement goes through the roundabout, instead of around. I can't vouch for its safety, as I haven't read any studies on it, but I'm sure it would improve efficiency. I actually proposed we try one of those at CT 82 and CT 85, where there's a huge left-turn (imagine right-turn in the UK) movement that will probably make the whole thing not work. My boss vetoed it on the grounds that people are stupid enough about roundabouts already, and adding another layer of complexity wouldn't help things.
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Aug 11, 2009 00:39
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10987 posted:One thing I've always wondered about stack interchanges, specifically 4-level stacks, is why they make everything cross at the centre, instead of spreading the ramps out (provided there's enough room). Like in this case, it *seems* that it would be cheaper to not have all the ramps cross directly at the centre, in order to cut down on the height required. The difference in cost might actually be marginal compared to the cost of the enlarged footprint, but I was wondering if there's any specific reason that it's done in this way.
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Aug 11, 2009 05:05
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Minister Robathan posted:One thing I've always wondered about stack interchanges, specifically 4-level stacks, is why they make everything cross at the centre, instead of spreading the ramps out (provided there's enough room). Like in this case, it *seems* that it would be cheaper to not have all the ramps cross directly at the centre, in order to cut down on the height required. The difference in cost might actually be marginal compared to the cost of the enlarged footprint, but I was wondering if there's any specific reason that it's done in this way. Someone posted a "three level stack" (I forget what they called it) early, which looks kind of like a spiral.
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Aug 11, 2009 09:38
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Ah here it is:Cichlidae posted:
What I don't get is why one pair of turning ramps is underneath the straight-through roads. It would make sense to me for both sets of turning ramps to go above, and the straight-through to stay level, since gravity would help you with your deceleration and acceleration. Socket Ryanist fucked around with this message at 09:52 on Aug 11, 2009 |
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Aug 11, 2009 09:40
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Minister Robathan posted:One thing I've always wondered about stack interchanges, specifically 4-level stacks, is why they make everything cross at the centre, instead of spreading the ramps out (provided there's enough room). Like in this case, it *seems* that it would be cheaper to not have all the ramps cross directly at the centre, in order to cut down on the height required. The difference in cost might actually be marginal compared to the cost of the enlarged footprint, but I was wondering if there's any specific reason that it's done in this way. Like Socket Ryanist said, the wider the turning radius, the faster they can go. The biggest benefit, though, is that there's only one structure to build. If you spread out the ramps, you'd need to build several more bridges. Every site has its own specific issues. This one could have environmentally sensitive areas near the interchange that preclude the use of anything bigger. Socket Ryanist posted:What I don't get is why one pair of turning ramps is underneath the straight-through roads. It would make sense to me for both sets of turning ramps to go above, and the straight-through to stay level, since gravity would help you with your deceleration and acceleration. Whether to put the ramps above or below the through roadways isn't a simple issue. The Green Book lists a few dozen different criteria to help decide, and there's no one answer that overrides everything else. In this case, though, having the east-west roadways go below and the north-south roadways go above accomplishes some pretty important tasks: - All elevation change is on the ramps, not the through roadways. Elevation change is a big cause of lost fuel, so it's important that the heaviest movements stay as level as possible. - If all the ramps were raised, either 95 would need to go up and down like a roller coaster, or the ramps would need to be built on huge bridges above the site. The latter is not feasible here because bedrock is 300 feet deep, and this whole thing was built on some incredibly expensive foundation. - The way it's set up, the ramps are parallel to and level with the roads onto which they're going to merge for several hundred feet in advance, making merging a little easier. One funny thing about this interchange that you may have noticed: the West to East through lanes exit from the right. Any guesses as to why this happened?
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Aug 11, 2009 12:20
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Cichlidae posted:One funny thing about this interchange that you may have noticed: the West to East through lanes exit from the right. Any guesses as to why this happened? Either that, or it has something to do with that lone, out-of-place looking building which looks like it would be in the way of making the through lanes stay on the left.
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Aug 11, 2009 14:57
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Cichlidae posted:Yeah, the cloverleaf there is currently the worst interchange in the state, in terms of violating modern standards. It even has a road coming in from the side to intersect 2 of the ramps. Luckily, that's all getting fixed in a few years, along with adding full access to the new US 7! Don't get your hopes up, though; it's never getting extended past Norwalk. Wilton's got the route completely blocked. You're right, it sure as hell isn't pretty. What's the deal with whiny Norwalk residents complaining about how it will change the atmosphere and character of the town? Norwalk doesn't have atmosphere or character, that's why they built Darien. While we're at it, what are your thoughts on this?the blue box,  http://maps.google.com/?ie=UTF8&ll=41.16503,-73.235035&spn=0.005751,0.011362&t=h&z=17 The purple box is all signal controlled, and the blue box is sign controlled. The lights in the purple box are phased 1; 2-3; 4. The first problem comes from the fact that 1 backs up and blocks the left lane in the underpass. This is compounded by 1 being a short signal and the fact that even someone running a late yellow on 4 at 30mph will leave them in the intersection when 1 turns green, compounded by the fact that people at light 4 (Exit 24 northbound on 95) tend to treat the first 5-10 seconds of light 4 as optional. Several times in the past few years, I have been waiting at light 1, which is on a short timer, and been blocked for the entire green light cycle by people running light 4. I come from Black Rock Tpk in the top left of the picture, and I usually head toward BJ's Wholesale, which is just past the bottom right road coming off the circle. The ideal way to do it would be to take light 1, move right, and take that road. I usually don't even bother because it's quicker to (check the Google maps link) take light 2, especially if 1 is backed up into the left lane, then turn left onto Kings Hwy, left onto Commerce Drive, and make a right on red onto Black Rock. In the blue box, 1 is unrestricted, 2 yields to 1, and 3 has a stop sign. When I'm heading back home and there's any appreciable amount of traffic, I get stuck at 2 for several minutes waiting for a break in traffic. The people at stop sign 3 are just plain hosed until 2 clears out. There's also the issue that unless you want to turn right and continue on Rt1, you have to weave to get to the stop sign in the middle that leads to Black Rock Tpk, the other major road in town, and the entrance to 95S, or left if you're some poor unfortunate motorist who is coming north on Black Rock and needs to head south on Rt1. There's also the wait at the stop sign and yield up top because traffic heading south on rt1 coming in from the top right has right of way. Here's the best I could do quickly  Black Rock Tpk is in blue, and both ways are down to one lane in this area. Rt1 is two lanes in each direction, and if you eliminate the wide shoulders and the super wide right lane under the bridge on the left, you can route four lanes under it, probably with a Jersey barrier median. This would get really messy if there were an accident under the bridge, but I think the curve in the road would help slow down traffic to the point that it's safe, and people won't be stopping under the bridge anymore. The northbound exit 24 ramp is now a bridge over the new rt1 and has a stop sign at the end. People who want to head south are SOL because they should have gotten off at exit 23 in the first place. The hosed up entrance to 95 northbound is pretty much the same as it is, but I'm not sure what to do with people coming from the left, so I left a stub there. Black Rock and rt1 now meet at a signal controlled intersection, and people going south on Black Rock who want to get on 95 northbound have to make a left turn onto rt1 then take their first right after the intersection. People heading north on Black Rock can turn right like they always have. The dotted line is a maybe, I'm not sure how it would affect traffic flow, maybe people should just take Kings Hwy to Commerce Drive. Red dots are stop signs. FakeUsername posted:So is that what this is? http://maps.google.com/maps?ie=UTF8&ll=41.231981,-73.220707&spn=0.002872,0.005681&t=h&z=18
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Aug 11, 2009 16:24
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Hey, check out this clusterfuck:  I'm including a link to the google map because a screenshot doesn't really capture the horribleness that is the 6th avenue freeway. http://maps.google.com/?q=&ie=UTF8&ll=39.725434,-105.014738&spn=0.005883,0.013733&t=h&z=17 The entire length of W 6th avenue is pretty terrible, but I have probably nearly gotten killed in this interchange more than anywhere else I've ever driven. The highway goes from 9 lanes (including the collector/distributor road and the ramps) at bryant, where the speed limit is 55mph, down to a 5 lane, one-way 30mph street as you get past the interchange to the east. The ramp geometry looks like it was designed by a 4-year-old with crayons. The acceleration lanes, where they exist, gain and loose lanes seemingly at random. The weaving, oh god, the weaving. I'm fairly sure that the Colorado DOT has this on their radar; I'm equally sure that the reason it hasn't been fixed yet is anytime someone looks at the cost estimates they just twitch a little and then pass out. Here's another interchange from the same road that's always loads of fun:  See the ramp from NB 121 (Wadsworth) to EB US-6? There is no acceleration lane there. None. You have from the last bend until where Vance street is to get to highway speed, which in this part is 65MPH. I can maybe make it to 55. Most people just swerve into traffic at about 40-45.
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Aug 11, 2009 17:50
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GWBBQ posted:Is demolishing Wilton an acceptable alternative? Norwalk's not the issue. Route 7 in Norwalk is pretty much finished. It's Wilton that's blocking the whole thing. I certainly would agree to demolishing Wilton. We could finish Route 7, and build a Route 106 freeway for good measure! quote:While we're at it, what are your thoughts on this?the blue box, Your plan's not bad at all! The problems I see are that 1 and Black Rock Tpke are at sharp angles and curve near the intersection, which is bad for sight distance. The side roads could also be a big problem. If I were going to fix up this mess, I'd go all the way. That means rebuilding the bridges, possibly removing the access to/from 95 altogether as there are exits on both sides, and getting rid of the circle. Massachusetts has plenty of them; we don't need to preserve the species. After working with it more, this intersection really is awful. The safest design I can come up with after a good 15 minutes of staring at it is to make a 4-way intersection underneath the freeway. The bridge, therefore, has to be pretty wide. Wide = expensive; don't expect Fairfield to fix this up for a looooong time.  Edit: New plan. Cede the land to Bridgeport and call it a day. Bridgeport has, by FAR, more dangerous intersections than any other city in the state. Cichlidae fucked around with this message at 23:45 on Aug 11, 2009 |
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Aug 11, 2009 21:41
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potato of destiny posted:Hey, check out this clusterfuck: Oh jeeze, the best way to fix that is just to extend the freeway more to the east. Barring that, it's simple enough to add a couple exit-only lane drops... but in this case, thanks to the nearby interchange and that idiotic ramp from W 6th Ave, that would cause some massive weaving. Ouch! quote:Here's another interchange from the same road that's always loads of fun: Substandard acceleration lanes can happen on any freeway, but when there's a cloverleaf involved, there's just no excuse! They could just stick a parclo in there and use the reclaimed land to add some accel lanes. It would fix the weaving, too! Edit: Because I like you 
Cichlidae fucked around with this message at 22:17 on Aug 11, 2009 |
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Aug 11, 2009 21:50
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Great thread, OP! Who knew traffic engineering could be so interesting? Mind answering a question from your days in Highway Advisory radio? Maybe it's just my area (I-64 in SE Virginia), but I can't get reception unless I'm already ON the highway. I want to be able to hear it before I get onto I-64, so I know whether I should stick with the secondary roads. Are they being deliberately broadcast on weak transmitters immediately adjacent to the road, or what? This has been the Hampton Roads Highway Advisory Radio. License number: KNJR 841. (Can you tell I've got a 30 minute commute and 610 AM as a preset on my car radio?)
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Aug 12, 2009 00:14
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JacquelineDempsey posted:Great thread, OP! Who knew traffic engineering could be so interesting? I can't speak for all HAR transmitters, but the ones we used in Rhode Island were incredibly weak. We placed the "beacons" that tell you to listen in about 3-5 miles away, and you couldn't hear the radio from there unless the terrain was relatively flat, or your car had an amazing antenna. The ranges were small intentionally: Rhode Island is a small state, and we wanted to be very responsive. Each transmitter had its own playlist, and they broadcast on the same frequency. That means, if two transmitters overlapped, there would be interference and neither message would get through. We had several pairs of transmitters with overlapping areas, and they had to be synchronized, which is rather difficult when you're sending them voice messages over dialup. Of course, this was mostly moot, since their audible range (1 mile) was much less than their theoretical range (5 miles). There are other ways to beat the interference. One is synchronizing the transmitters, like we did, but that means less "detail" in the messages they gave. Another way, which is used in Connecticut, is to use different frequencies. A third way is to decrease the transmission power. So we had this weak AM antenna (40 Watts or so) broadcasting about a mile, and carrying a 30- to 90-second playlist. On the freeway, you're in range for two miles, tops, and that means about 2 minutes of listening time. (Being in congestion is another matter, and for that, I wholeheartedly support the HAR network.) So let's have a little timeline! 0 minutes: You see the beacon, telling you to tune in with its flashing beacons. This little sign cost $10,000. No joke. 0.5 minutes: You are trying to figure out whether it's worth changing the station, or if it's just some ozone advisory or stadium event thing. 1.0 minutes: You tune to the radio station, but there's a small shrub somewhere in the 2 miles between you and the transmitter, so you hear fuzzy static. 2.5 minutes: You can hear enough to make out a fuzzy message that there's been an accident ahead. The message ends and you're treated to another 60 seconds of useless reminders and station callsign. 3.5 minutes: You fly past the transmitter, ear craned to the dashboard in eager anticipation of the important message. Just as it comes on, you rear-end a semitrailer at 75 mph. Whoops.
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Aug 12, 2009 00:55
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Back to bikes: Are there any guidelines in the Green Book or any of the standard texts regarding bicycles? You said you prefer separate infrastructure (trails) to bike lanes, is that to handle recreational cyclists or people trying to go places? Unfortunately I live in a rural area, so I don't even get access to bike trails, but I read a lot of complaints that they don't go anywhere useful so they are mostly left to the recreational crowd. How much consideration do bicycles get in traffic engineering? More than none? On my daily commute, I have no other option but to ride in the lane of a two-lane, 45 mph road, for at least two miles on the way to/from work. I get passed by a lot of cars, pickups, and dump trucks at 45 mph. While it still scares the poo poo out of me when a 40-ton trucks passes me with about a foot and a half of clearance at those speeds, I think making the right-most lanes several feet wider would make me feel safer (even if it might not actually be safer). Is that enough of a safety issue to redesign a road, or are bikes just not statistically significant enough to include in road planning? Also, how much does it cost to retroactively place light rail and other train systems in U.S. cities? Is it going to happen in cities where it doesn't already exist?
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Aug 12, 2009 01:01
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drat, I really like your design for that Wadsworth/6th ave. interchange. After hunting around on cdot's website, I managed to find the EIS they apparently did on that, and it looks like they want to go with a tight diamond with a loop in the upper left quadrant (from WB US6 -> SB Wadsworth). This, apparently, will involve a great deal of knocking down houses, so I suppose CDOT feels they haven't been picketed enough lately (it's mostly been RTD, our regional tranist authority, as they get ready to install about 120 miles of rail transit over the next 6-7 years). As I was poking around, I found another thing that I wanted to ask about. There are a couple of heavily used bridges that form part of I-25, and there was mention of the "sufficiency rating" being 20.2 and 22.8, with 50 being considered "acceptable." I guess what I'm wondering is what the threshold is for "oh god, oh god, we're all going to die."
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Aug 12, 2009 01:09
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