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Millstone posted:Tell me where to go to become awesome at mastering whatever the gently caress this is You must first spend four years as an apprentice in the Noble Order of the Electron. You will face many perils, but if you survive, then you must undertake your most dangerous quest to date: achieving journeymanship as an electromage in the Royal Carriage Department. After years of tireless work and impossible battles, you will become the most honored Master of Whatever the gently caress This Is!
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Nov 25, 2010 14:20
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Millstone posted:Tell me where to go to become awesome at mastering whatever the gently caress this is grover fucked around with this message at 20:15 on Nov 25, 2010 |
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Nov 25, 2010 20:12
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Cichlidae posted:You must first spend four years as an apprentice in the Noble Order of the Electron. You will face many perils, but if you survive, then you must undertake your most dangerous quest to date: achieving journeymanship as an electromage in the Royal Carriage Department. After years of tireless work and impossible battles, you will become the most honored Master of Whatever the gently caress This Is!  grover posted:Speaking on a broader basis, controls work is complicated as hell, but makes a lot of sense once you know what each of the bits are. You can learn a lot by taking the right electives in college, but ultimately much of it is simply experience; people who are really really good at it and unable to unfuck broken systems are virtual gods. I was really good at digital systems in college. It was my highest mark in both courses (I and II). Would this sort of thing be a natural progression?
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Nov 27, 2010 00:59
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Millstone posted:
Depends on how much is analog and how much is computer-controlled. I think Cichlidae broke down somewhere what the components are. What's all that hard wiring on the screw terminals? It looks like they go back into the main units at the top.
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Nov 27, 2010 09:05
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Derpes Simplex posted:Depends on how much is analog and how much is computer-controlled. I think Cichlidae broke down somewhere what the components are. What's all that hard wiring on the screw terminals? It looks like they go back into the main units at the top. Well I mean like, traffic/intersection/interchange planning in general. A signal is just a logical procedure that should move traffic as efficiently as possible based on a timer or some triggers, I'd like to get into that world for reals
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Nov 27, 2010 09:37
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Derpes Simplex posted:Depends on how much is analog and how much is computer-controlled. I think Cichlidae broke down somewhere what the components are. What's all that hard wiring on the screw terminals? It looks like they go back into the main units at the top. You've got a pretty good mix of analog and digital. The bus bars in the cabinet are mostly analog input from the loops and current out to the signal heads. There are electromechanical relays for pre-emption. The job involves a whole lot of wiring, splicing, arranging conduit, and the like. Once the controller is involved, it's lots of digital work, but very little wiring, except for the pinouts on the NEMA ports.
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Nov 27, 2010 19:52
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Cichlidae posted:You've got a pretty good mix of analog and digital. The bus bars in the cabinet are mostly analog input from the loops and current out to the signal heads. There are electromechanical relays for pre-emption. The job involves a whole lot of wiring, splicing, arranging conduit, and the like. Once the controller is involved, it's lots of digital work, but very little wiring, except for the pinouts on the NEMA ports. I've been trying to get into an electrical apprenticeship too, but it's all full up where I am, so that will be right up my alley. Let's do this. I'll update you in 2014.
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Nov 27, 2010 21:57
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Would a roundabout make much more sense for this fustercluck of an intersection? I can understand not wanting a light since route 1 is a rather busy road, but coming south from Rt 88 and needing to go south on 1 means you're crossing 3 roads.
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Nov 29, 2010 22:15
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Lobstaman posted:Would a roundabout make much more sense for this fustercluck of an intersection? I'd need to see the volumes to make a definite assessment, but yes, that looks like an excellent place for a roundabout. The right-of-way is there, the approaches look fine, the terrain is flat, and it would very much simplify geometry, thereby reducing accidents. The only thing that's a bit tricky is the presence of a bike path, but that could easily be moved away from the intersection (as it is now) to keep things safe.
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Nov 29, 2010 22:47
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Speaking of roundabouts, here's the most difficult one I know of. clicky It has: 1. Cars 2. Pedestrians 3. Bicycles (the outer ring is the bike lane) Relevant Dutch laws: 1. Pedestrians walking over the zebra-lines have the right of way over everything. This also applies to pedestrians who are not on the zebra-lines yet but show intent of wanting to cross it. 2. Vehicles who are on the roundabout have the right of way over vehicles that are not on the roundabout. 3. Traffic that goes straight has the right of way over traffic that wants to turn. In this case, it means that when a car wants to leave the roundabout, but there's a bicycle to its right that wants to stay on the roundabout, the bicycle has the right of way. 4. Hitting a bicycle with your car is punished very heavily, and the car pretty much always gets the blame. Bicycles have a special status here. Getting on the roundabout : yield to pedestrians who want to cross the street, yield to bicycles that are on the roundabout, yield to cars that are on the roundabout. Leaving the roundabout : yield to pedestrians who want to cross the street, yield to bicycles who want to stay on the roundabout. This last one is the trickiest, because they come up from your blind spot, and many of them don't signal when they want to turn, making you assume you have to yield to them. So, you get a lot of cars that have to brake hard on the roundabout because they have to yield to bicycles, which complicates things further because you have to look around a lot. This roundabout is very busy during rush hour, with lots of bicycles.
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Nov 30, 2010 10:07
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Captain Corny posted:Speaking of roundabouts, here's the most difficult one I know of. Bicycles are the only major group that don't benefit from roundabouts, safety-wise. Punishing motorists more severely for colliding with them likely makes them think twice, but that hesitation can cause accidents as well. If the bicycle volumes are low, it's easiest for bicyclists to dismount and use the pedestrian crossings. In your situation, though, with so many of them, I doubt bicyclists would want to dismount every time they come to a roundabout. I've seen some roundabouts with separate levels for bikes and foot traffic, but that's obviously an expensive exception. Do you think having a separate bike lane on the outside of a roundabout really helps? From what I've seen, it's best for them to merge with vehicles and go through the roundabout like a car, making them more visible to drivers.
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Nov 30, 2010 13:42
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Let's say you have a T intersection of a low volume road (entry to a small neighborhood) with a high volume road (main path from the center of town to the highway). Currently there is a stop sign and dedicated lanes for left and right turns. This works well for the majority of the day where the volume on the main road is reasonable, but between about 3 and 7 PM turning left becomes a game of timing and liberal application of throttle. Is there any lighting configuration which could allow free flow on the main road with a stop sign like ability for the left turners to jump out when there's an opening for the majority of the day, but could also detect when someone's been waiting to turn for a long time and give them a short period of right-of-way? The way I imagine it, it could be done with a normal set of lights that would basically be in yellow blink for the main road and red blink for the residential road the majority of the time, then switch to a "normal" mode of operation if it detected a vehicle in the left turn lane for more than some X time before going back to blink. Unfortunately I'm sure this goes against a number of standards and simple driver expectations.
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Nov 30, 2010 16:47
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Cichlidae posted:I've seen some roundabouts with separate levels for bikes and foot traffic, but that's obviously an expensive exception. Do you think having a separate bike lane on the outside of a roundabout really helps? From what I've seen, it's best for them to merge with vehicles and go through the roundabout like a car, making them more visible to drivers. I recently saw some report on TV about this, apparently it's best to have bike paths in a square shape around the roundabout, separate from the roundabout itself and with crossings at every leg, so they don't end up in blind spots and are separated from the cars. Although I think it'll make them more likely to use the roundabout as a shortcut... Roundabouts with a lane for bikes and roundabouts with pedestrian and bike crossings at the legs are pretty common, but roundabouts that have both of these things like the one Captain Corny posted are fortunately pretty rare, at least in the north of the Netherlands. Entropist fucked around with this message at 17:24 on Nov 30, 2010 |
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Nov 30, 2010 17:22
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Entropist posted:Roundabouts with a lane for bikes and roundabouts with pedestrian and bike crossings at the legs are pretty common, but roundabouts that have both of these things like the one Captain Corny posted are fortunately pretty rare, at least in the north of the Netherlands. Example
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Nov 30, 2010 17:36
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Captain Corny posted:A more common (and better) design in the Netherlands is having the circular bike lane physically separated from the car lane, and having the bicycles yield to cars when they cross the roads. They take up more space though, which is probably the reason why they chose the more compact option in my first example. They had this in Leeuwarden in the center, but recently changed it so that cars have to yield to the bikes and pedestrians instead of the other way around. It's certainly effective for traffic calming, it sometimes causes traffic jams when a continuous stream of people is walking between the center and the station  And since drivers have to watch for both peds and bikes at each roundabout, they are usually careful enough to make it work.
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Nov 30, 2010 19:33
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That's the way it is in Rotterdam. Sometimes I dream of having bicycle fly-overs, and then I wake up in a icy world where people would never be able to use them.
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Nov 30, 2010 20:15
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Entropist posted:They had this in Leeuwarden in the center, but recently changed it so that cars have to yield to the bikes and pedestrians instead of the other way around. It's certainly effective for traffic calming, it sometimes causes traffic jams when a continuous stream of people is walking between the center and the station
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Nov 30, 2010 21:01
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wolrah posted:Let's say you have a T intersection of a low volume road (entry to a small neighborhood) with a high volume road (main path from the center of town to the highway). Currently there is a stop sign and dedicated lanes for left and right turns. This works well for the majority of the day where the volume on the main road is reasonable, but between about 3 and 7 PM turning left becomes a game of timing and liberal application of throttle. The main problem here is the indication shown on the side street. Either they'd get a flashing red, which works like a stop sign, or a solid red, which is an actual signal. With what you're describing, it would change from flashing to solid after a car had waited for several seconds. Someone who's already begun pulling into the intersection would inadvertently run the red. But there is a solution! Use a normal signal, let it rest on the artery phase. Put detectors on the side street, with an 8-second (or longer) delay. Set them to non-lock. Set it to flash from mid-evening to early morning, like we do with most low-volume signals. Not ideal, but it works. Personally, I'd like to see a right-out (no left turn) used. Eliminates that expensive signal equipment, frees up traffic on the main road, and reduces accidents significantly. Drivers can always find another way out, or turn around at the next side street. Putting a signal on the side street will eventually bring a lot more volume to the street, pissing off residents and traffic engineers alike.
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Nov 30, 2010 23:28
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Cichlidae posted:Bicycles are the only major group that don't benefit from roundabouts, safety-wise. Punishing motorists more severely for colliding with them likely makes them think twice, but that hesitation can cause accidents as well. If the bicycle volumes are low, it's easiest for bicyclists to dismount and use the pedestrian crossings. In your situation, though, with so many of them, I doubt bicyclists would want to dismount every time they come to a roundabout. Please don't do this  This would be a terrible solution even over here in Roundabout Country, let alone in the US, where roundabouts are apparently still considered to be the spawn of the devil himself. No offense.The seperate bike paths are there for good reasons. Keeping the poor and vunerable bicyclists as far away as possible from large moving metal objects. Ensuring the flow of car traffic by not having slow bicyclists in their way. It also prevents collisions between bicyclists and cars when cars move out of the roundabout circle. By the way, how's the roundabout spreadsheet working out for you?
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Dec 1, 2010 11:28
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Dutch Engineer posted:Please don't do this The spreadsheet is awesome. I've used it for a few projects, though I'm still the only one who can, because I can't get permission to translate it into English. You were right; the bureaucrats there aren't particularly helpful.
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Dec 1, 2010 13:29
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Cichlidae posted:The spreadsheet is awesome. I've used it for a few projects, though I'm still the only one who can, because I can't get permission to translate it into English. You were right; the bureaucrats there aren't particularly helpful. Captain Corny fucked around with this message at 23:18 on Dec 1, 2010 |
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Dec 1, 2010 23:16
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Captain Corny posted:Why not just ignore the bureaucrats, translate it yourself and spread it out to your coworkers? Good ideas have a way of gaining popularity when you make them accessible. Because all the text fields are locked and I don't have the password.
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Dec 2, 2010 01:39
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Cichlidae posted:So, those billboards too bright? Distract you from the road? Call your state representatives and try to get a state law passed banning them. May as well give it a shot! I saw your advice and began looking up my state reps, drafting a letter, etc. Then a realization struck me. This is Atlanta. The companies owning or running the worst offenders through downtown are Delta, Airtran, Coca-Cola, Turner, and Georgia Tech. Hoping a letter is going to encourage my reps to go against any one of them is probably quite foolish. Dammit. But you're quite right, that would be the way to go. And thanks for the background info on that for your area. We don't have anything that would be mistaken for any sort of official signage, though I couldn't say whether that's due to regulation or that it's just not in line with these companies' marketing plans.
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Dec 2, 2010 15:10
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Iridium posted:I saw your advice and began looking up my state reps, drafting a letter, etc. Then a realization struck me. The ire of your letter won't be directed at those specific companies, it would be directed at the owners of the billboards (Viacom, Lamar and Clear Channel are among the largest). The companies simply rent space so they wouldn't be directly affected, they'll just have to come up with non animated advertising.
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Dec 3, 2010 14:23
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teacup posted:I remember hearing from a friend about a really interesting british documentary on traffic flow and the British traffic system... like how traffic jams ebbed and flowed through a highway, I think it also dealt with power lines and everything too. I think you mean The Secret Life of the Motorway: http://www.bbc.co.uk/programmes/b007xr62 and The Secret Life of the National Grid: http://www.bbc.co.uk/programmes/b00vfc7b (writeup here) It's not available to stream any longer, even for UK people, but i've seen it available on Youtube and Vimeo - Google Video Search should find it. Each series has three episodes. All essential stuff for infrastructure geeks! Apparently there's a Secret Life of North Sea Oil too.
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Dec 5, 2010 12:04
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meltie posted:I think you mean The Secret Life of the Motorway: http://www.bbc.co.uk/programmes/b007xr62 Very cool documentary. It's amazing how many parallels there are between the construction of the M1 and the A19 I worked on in France: they were both about 100 km long, built over virgin terrain in essentially a straight line, split into four contracts, massive undertakings in their own right with a lot of migrant workers, and completed on-time and on-budget. It was rather nostalgic to watch! The segments on sign design and safety improvements are also quite relevant to me. It's surprising to see that they got sign design right on the first try, with mixed-case lettering and white-on-blue text. It's taken us decades of revision to put mixed-case lettering on more signs, and that may not even happen, given the current hullabaloo about street signs.
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Dec 5, 2010 17:46
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He might have also meant this: http://www.bbc.co.uk/britainfromabove/stories/transport/motorwaymadness.shtml (not sure if this is available outside of the UK) nozz fucked around with this message at 01:13 on Dec 6, 2010 |
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Dec 6, 2010 01:05
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noblergt posted:He might have also meant this: It works for me. A good example of shock-wave traffic jams and the way they develop. Here's something I wrote about it for an article: --- Congestion spreads like a wave. From the appearance of the first brake light, drivers upstream start to reduce headways, gradually closing in on the car in front of them. This reduced and rapidly closing headway makes drivers uncomfortable, forcing them to brake as well. Since speed differentials are so high here at the back of the queue, inattentive drivers are likely to cause accidents. Keep in mind that some older people take 4 seconds to react the next time you’re at the back of a queue; you’ll spend more time watching your rear-view mirror than looking forward. What happens next depends on the LOS of the road. When the incoming flow rate is low enough, this shock wave quickly dissipates. Approaching drivers have enough extra headway to maintain their speeds, and the spark of red light stops where it began. If the road is already operating at LOS E, however, that momentary drop in speed is enough of an ember to ignite an inferno of congestion. The denser the incoming vehicles are, the quicker that conflagration will spread upstream. In the worst case, when all lanes are blocked and the road was already at capacity, this shock wave can travel upstream at 12 mph / 19 kph. Now that the arrival rate (demand) is higher than the departure rate (supply), vehicles begin to queue. In mathematical terms, the length of the queue is the integral of the difference between supply and demand. The second integral provides the total delay. Once either the demand decreases or the supply increases, the queue reaches its maximum length. However, the upstream end could still continue building for some time. This is why we sometimes get caught in congestion with no apparent cause; congestion outlasts its cause.   
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Dec 6, 2010 02:43
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I can't view that link  I saw an interesting test on TV the other day that really showed the highway bunching effect- a while bunch of cars driving in a ring with perfect spacing until one got a little too close, braked a little too hard, and it started a chain reaction. I wonder, though, what the difference would be if the aggressiveness of the drivers were dialed up? It might create more braking, but they'd also be able to recover quicker and I wonder if that would stop the chain reaction or just make it worse.
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Dec 6, 2010 02:56
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grover posted:I can't view that link More aggressive drivers tolerate lower headways and are faster to depart a queue, so I imagine they'd reduce congestion. If we gave every driver Formula 1 cars, there would be no jams at all. (Alright, maybe not, but driving would be a lot more fun!)
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Dec 6, 2010 03:00
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There'd be no traffic jams because 99% of drivers wouldn't be able to move more than 10 feet without destroying the engine 
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Dec 6, 2010 03:13
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I just finished reading Tom Vanderbilt's Traffic over my plane rides to/from Florida this weekend. I had started it a few months back but hadn't finished it for a variety of reasons. Really interesting book if you like to read about the trouble of traffic.
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Dec 6, 2010 06:16
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Dutch Engineer posted:Please don't do this From the studies I've seen, most car/bicycle collisions occur in intersections when the bicycle is riding on something other than a street (sidewalk/bike path) followed by the "right hook" (essentially being merged into or being cut in front of when riding in the shoulder). The problem with the dutch solution is that it creates a whole lot of the first situation. Lots of points where a bike can get hit unless: 1. Drivers are paying attention, looking for non-cars (possible in the Netherlands, not in the US). 2. Bicycles or cars have a stop sign/light, slowing everything down. Occupying the full lane of a round-about is going to be the safest way around it in my opinion unless there is a bypass that avoids crossing a bunch of roads. Too many engineers try to create bike paths everywhere and seem to make paths less safe than riding on the road. If there are a bunch of crossings with roads, it can cause a lot of issues.
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Dec 6, 2010 08:05
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People watch for bikers in any city where there are enough of them. I know you can't drive in berkeley or san francisco without watching for bikers.
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Dec 6, 2010 08:09
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Socket Ryanist posted:People watch for bikers in any city where there are enough of them. I know you can't drive in berkeley or san francisco without watching for bikers. The issue is when bicycles ride off-street on sidewalks and half-assed bike paths. No one is looking for something moving at 20mph. Plus there can be visibility issues. And still many people don't. Bikes and peds getting hit by cars isn't exactly uncommon in the bay.
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Dec 6, 2010 08:17
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Even though it's not really about transport that National Grid documentary that meltie linked is really loving interesting so I really recommend you watch it.
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Dec 6, 2010 16:43
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grover posted:I can't view that link I bet you'd get the same results, just with a quicker cycle.
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Dec 6, 2010 23:46
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IOwnCalculus posted:I bet you'd get the same results, just with a quicker cycle. If it was just going around in a loop, that's pretty likely, because when they accelerate faster, they'll just end up tailgating the guy in front of them to start the process anew. In a straight line, assuming the initial disturbance is only momentary, aggressive drivers would help it recover a great deal faster. Queue arrival rate and departure rate are really the two critical figures. Edit: Here's a bit more detail. Aggressiveness is going to affect these two factors like so: Lower headways provide the potential for higher flow rates, which means a higher arrival rate. However, it's not really fair to compare a 2500 vphpl aggressive driver stream to an 1800 vphpl group of timid drivers. If we assume that the volumes stay the same, and only the aggressiveness changes, the arrival rate stays the same. Departure rate is something you can measure yourself at any stoplight. It essentially is based on how soon a driver sees that the light is green, accelerates, and clears the stop bar. We generally assume (outside aggressive areas like Connecticut) 4 seconds for the first car, and 2 for each subsequent car, leading to an eventual "saturation flow rate" of one car per lane per 2 seconds, or 1800 vphpl. This is the rate that vehicles can depart a standing queue, and it's also the theoretical maximum flow rate for any road that has stops (any non-freeway). Aggressive drivers will accelerate faster and hug the bumper of the car in front of them, leading to a higher departure rate and quicker queue dissipation. Cichlidae fucked around with this message at 22:52 on Dec 7, 2010 |
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Dec 7, 2010 13:23
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I'm really excited that our city's first SPUI being opened up on Saturday. I've tried to explain how this interchange would be beneficial to my coworkers thanks to the knowledge from this thread, but they all have dismissed it in a "if it ain't broke, don't fix it" kind of way (despite the fact the intersection in question was always horrible in all traffic situations). We also opened a Michigan left, and it bugs me how many people refuse to pay attention and just turn like they normally would.
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Dec 10, 2010 21:30
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kimcicle posted:I'm really excited that our city's first SPUI being opened up on Saturday. I've tried to explain how this interchange would be beneficial to my coworkers thanks to the knowledge from this thread, but they all have dismissed it in a "if it ain't broke, don't fix it" kind of way (despite the fact the intersection in question was always horrible in all traffic situations). Hopefully, their impressions will change once they start driving it. Roundabouts tend to have that effect; public response improves significantly after opening. Let me know what they think once they've driven through it a few times! kimcicle posted:We also opened a Michigan left, and it bugs me how many people refuse to pay attention and just turn like they normally would. That's something that only enforcement will be able to fix. It's very hard to ask police to enforce something, unfortunately, so it's likely people will keep on doing it until they create a bad enough accident problem that the cops take notice. It sounds like your transportation department could use some better PR. Between publicizing the new improvements and teaching the public how to use them, the burden falls on the DOT to inform drivers.
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Dec 10, 2010 23:13
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