|
This thread is really fascinating - great job Cichlidae! I thought I'd ask your opinion about the most high profile traffic project near me: the central London congestion charge.  Basically, it's a large chunk of the very centre of London that will cost you £8 to drive in on weekdays, and there are a LOT of cameras to make sure you pay up. There was a big debate about it when it was introduced, and since then it's grown and become more expensive. This is the current extent of the zone:  Personally, I don't mind it as I don't actually have a car, I find that London's public transport network is extensive and frequent enough not to need one. What I wanted to ask is if a huge blanket toll area is an effective traffic management scheme? It's pretty hard to find hard numbers on how much congestion has been effected, although it is pretty difficult to measure. The wikipedia article says there is a 16% drop in overall traffic since the introduction of the scheme, but that the effect is negligble in the busiest time, the morning rush hour. Alternatively, is it just a moneymaking exercise? It does generate large profits, but at least they're put back into Transport for London to fund buses and stuff v  v(You've mentioned shortages of funds: if you could get away with this, would you?) Edit: Actually, I forgot to mention that the mayor who came up with this was nicknamed Red Ken, so I'm pretty sure the real reason behind it is "anyone who can afford to drive in Central London can afford to subsidise buses for the working class." I'm still interested in the Traffic Engineering opinion though! Ripper Swarm fucked around with this message at 14:59 on Oct 7, 2009 |
#
?
Oct 7, 2009 14:49
|
|
|
|
| # ? Apr 28, 2024 12:04 |
|
|
Lucid Smog posted:Yes, very thorough, thanks. I've never seen what I believe is tape. This must be the not-paint paint that they put down. The road looks to be milled down at least 2", and it's miles of pavement on an 8 lane interstate (I-695 in Maryland)... so it's not really a small job. How deep does the epoxy for normal lane markings go into the pavement surface, or is it all superficial? Epoxy or paint might go a quarter inch down, and the thermoplastic can probably penetrate a bit more, but it would be very difficult to see since it would only fill in the little air holes between the aggregate. If the pavement markings you're seeing are old, they're probably the layer of paint or epoxy put down the last time the road was paved, on the base course. The milling operation took off the top course(s), and those particular markings are once again exposed to the light of day.
|
|
#
?
Oct 7, 2009 16:38
|
|
|
Ripper Swarm posted:This thread is really fascinating - great job Cichlidae! Well, I'm rather conflicted about this. From a traffic engineer's perspective, it's an effective and high-tech way to reduce congestion in downtown areas and charge only those who use them. One could readily argue that a gas tax is unfair because it costs the same to drive on an uncongested road as on a congested one. On the other hand, as a private citizen, I'm quite worried about how pervasive this monitoring is. I'd much rather pay a flat monthly fee and use the roads whenever I like than have my movements monitored and tracked. I much prefer Germany's restriction on what types of vehicles can travel in cities. Let's look at what we could do with this technology. First off, tracking every vehicle through a system could lead to optimized signal timings and real-time routing, which would have a very positive effect on capacity. However, this could be offset by people trying to avoid downtown and just congesting roads on the fringe of the city, or that one non-toll corridor through central London. As you said, peak-hour congestion hasn't really decreased. It makes sense that people would consolidate their trips in off-peak hours, but everyone needs to get to work and get home somehow; it's very difficult to consolidate that kind of trip without encouraging carpooling and mass transit. As to whether it's fair, I'd argue that it is. Being able to drive isn't a right. We already toll bridges and motorways, why should a CBD be any different? There are alternatives; as you pointed out, it's quite possible to get around in London without a car. The factor that matters most to me is why the charge is being collected. Does the money go to maintaining other roads, improving transit, or just get dumped into the general fund? Was the charge put in place just to reduce congestion, or was the purpose to shift people away from cars and toward the Underground? It's a very complex issue, and I'd like to see how things pan out before I make a final judgment.
|
|
#
?
Oct 7, 2009 16:54
|
|
|
I had a look around the Transport for London website and found they publish all their documents online. The latest Impact Monitoring one is here, if you're seized by an urge to read 227 pages of government report http://www.tfl.gov.uk/assets/downloads/sixth-annual-impacts-monitoring-report-2008-07.pdf From it, all the profits from the scheme by law have to be reinvested in TfL. In 2007/08, this was £137 million, of which £112 million was spent on improving the bus network (they give examples of improving bus shelters and providing policing on the network) and most of the remainder was spent on road/bridge maintainence. The results they highlight are that traffic in the whole zone is down about 20% on pre charge levels, and bus and cycle commuter numbers are up 12% and 6% respectively. However, congestion hasn't dropped, although they blame that on some major roadworks that dropped capacity during the monitoring. Interestingly, the roads running around the Zone actually became less congested: they anticipated that people would try to avoid it and improved the traffic management to handle it beforehand. That's some pretty impressive foresight for a British engineering project! With most of the money spent on buses and the rise in bus passenger numbers, it looks like the aim was to encourage/force people to get out of cars and into mass transit or on bikes. This makes sense really, given how extensive the public transport in the area is. There's a reasonably good cycle path network too. I agree the monitoring is pervasive, but London already has the highest rate of CCTV cameras per capita in the world so this sort of privacy argument is unfortunately nothing new- in fact, the Government was looking into tracking every car journey made anywhere in the country by satellite a few years ago. I didn't find anything on whether they are integrating the technology with the regular traffic monitoring. It's run by a contractor, but it might be designed to work with the existing system anyway, you never know. Privacy issues aside, I have to say as I'm looking into it, it does seem more and more a good idea. All the City bankers can still drive their Porsches to work, but now they're helping make the bus commute a bit better for the guy who cleans their office. I don't imagine you could get away with such a blatantly communist scheme in the US 
|
|
#
?
Oct 7, 2009 18:26
|
|
|
Ripper Swarm posted:I had a look around the Transport for London website and found they publish all their documents online. The latest Impact Monitoring one is here, if you're seized by an urge to read 227 pages of government report http://www.tfl.gov.uk/assets/downloads/sixth-annual-impacts-monitoring-report-2008-07.pdf Thanks for the information; that's actually quite encouraging. It'd be interesting to see this system spread across the entire country. Of course, I'm sure the prices would be lowered, or else nobody would be able to afford to drive! Thinking about the logistics, it would probably be easiest to have radio or GPS transponders on each car (though I'm sure some people would try to disable theirs). Each car's location could be collected every minute or so, then the fees collected on an ongoing basis. After that, the data could be stripped of personal data and handed over to the traffic engineers for analysis. What would be tricky is determining prices for each region and type of road. It would be ideal to have rates that change to reflect congestion in real-time, but the legality of changing the price without notifying the driver is a bit dubious. Perhaps there could be an integrated display in the car showing the going rate, much as we have now for fuel mileage. Of course, if you're on the motorway, hit a jam, and the price jumps from 10 pence to 10 quid/hour, and it takes 20 minutes to get off the next exit, could you contest the charges?
|
|
#
?
Oct 7, 2009 21:18
|
|
|
Doesn't NYC do a similar thing? I seem to recall it cost $8 to drive into Manhattan (it was free to leave). Granted, once your car is already in Manhattan you could drive around for months without paying anything more as long as you never left. They also gave huge discounts to people who carpool - something like if you had 4+ people in the car it would only be $2 instead of $8. My friends and I were waiting at a bus stop in New Jersey for the bus that would take us into Manhattan and some dude stopped his car there and offered us a free ride across so he could save himself the $6. Last time I visited was years ago, though, so who knows what's changed.
|
|
#
?
Oct 7, 2009 21:57
|
|
|
Cichlidae posted:Thanks for the information; that's actually quite encouraging. It'd be interesting to see this system spread across the entire country. Of course, I'm sure the prices would be lowered, or else nobody would be able to afford to drive! Thinking about the logistics, it would probably be easiest to have radio or GPS transponders on each car (though I'm sure some people would try to disable theirs). Each car's location could be collected every minute or so, then the fees collected on an ongoing basis. After that, the data could be stripped of personal data and handed over to the traffic engineers for analysis. They'd have to do it by mile, not time; I can't imagine the road rage people would give you if you managed to close a motorway and started costing them serious money! I imagine pricing would be dependant on type of road/time of day so being on a major motorway at 9am would be most expensive and being on a rural back road at 3am would be practically free. That would mean if you do the same route each weekday, it would cost you the same amount each day. There aren't any solid details on how this would work yet, they're running the technical feasibility study right now which should report next year. If the technology works, I gather they're aiming to implement this around 2015 should the politicians decide to press ahead with it. I'm sure I don't need to tell you it's a deeply unpopular idea. If you want to read the official take, it's on the DfT website. Edit: Choadmaster posted:Doesn't NYC do a similar thing? I seem to recall it cost $8 to drive into Manhattan (it was free to leave). Granted, once your car is already in Manhattan you could drive around for months without paying anything more as long as you never left. I thought NYC just had tolls on the bridges, so that would be a one-off payment on that particular road only? It is the same idea as a toll road, but on a much bigger scale. Edit x2: Yup, there's no physical toll system save the enforcement cameras. Ripper Swarm fucked around with this message at 22:12 on Oct 7, 2009 |
|
#
?
Oct 7, 2009 22:04
|
|
|
Choadmaster posted:Doesn't NYC do a similar thing? I seem to recall it cost $8 to drive into Manhattan (it was free to leave). Granted, once your car is already in Manhattan you could drive around for months without paying anything more as long as you never left. I think there are tolls for crossing the Hudson river, eastbound only. Surely there's a way to get into the City without paying tolls, though. I could just take local roads in through the Bronx. It's not so much an entry fee, but rather a toll on bridges and tunnels, which happen to be the best way to get into and out of Manhattan. On the other hand, London's system covers nearly every street, and, I assume, without toll booths.
|
|
#
?
Oct 7, 2009 22:08
|
|
|
Cichlidae posted:What would be tricky is determining prices for each region and type of road. It would be ideal to have rates that change to reflect congestion in real-time, but the legality of changing the price without notifying the driver is a bit dubious. Perhaps there could be an integrated display in the car showing the going rate, much as we have now for fuel mileage. Of course, if you're on the motorway, hit a jam, and the price jumps from 10 pence to 10 quid/hour, and it takes 20 minutes to get off the next exit, could you contest the charges? You get charged a posted price on entry. It goes up and down with traffic volume and is designed to keep traffic above 50mph. It appears to work pretty well, but then, it is only like 8 miles. The congestion charge actually works fairly well (I used to live there, though carless), but I'd only want it in cities with good public transit (like London). I'm not sure I agree with the free/reduced cost entry for hybrids and stuff. It defeats the whole purpose of the congestion charge, which is to reduce congestion. A prius takes up as much space as a focus on the street. I'd rather see a discount for cars with more than 50% of seats filled.
|
|
#
?
Oct 7, 2009 22:23
|
|
|
nm posted:They have a much smaller scale version of this in Minneapolis with the reversible lanes. The report that Ripper Swarm linked says they're not looking to implement it nationwide, but they're studying it anyway. It'll be interesting to see what results, because Connecticut, as I mentioned, has banned tolls for 20 years now. However, a congestion charge is not a toll, and I could definitely see something similar being implemented in 10 years when the technology is mature and our bridges are falling apart from lack of maintenance funds.
|
|
#
?
Oct 7, 2009 22:28
|
|
|
Cichlidae posted:our bridges are falling apart from lack of maintenance funds. 
|
|
#
?
Oct 7, 2009 22:35
|
|
|
Wow. Great thread. Took me two full days to read through it all. That said, I did have a question that never came up. Hopefully, the guy who works in Houston knows more about the politics behind it, but if Cichlidae can give any insight, that would be great. Just before I got my driver's license, way way back in 1990, someone decided that the interstate (I-10) between Houston and Beaumont needed to be completely redone. In particular, the area around Baytown needed extensive work. And so it started. In 1999, when I started working in Houston, and eventually moved to Austin, there was still a lot of work being done on this stretch of road. To be fair, it was "only" nine years then and approximately 75 miles of road, so whatever, I could understand. The Baytown section was finally starting to shape up after all this time and looked like it would be complete sometime in the near future -- and some of it was! Of course, now, nearly 20 years later, I drive back home to see my family in Beaumont and I realize that construction is still going on and the freeway is as torn up as ever, and it seems that almost nothing has really been completed. For 20 years I've waited for this road to be done and to have a half decent trip from Houston to Beaumont unimpeded by construction and poor surface conditions and lane control issues. Yet, I realize I've never driven this stretch of highway, in particular, the 10 or so mile stretch through Baytown, without some kind of eternal construction going on. What is going on here? Why do they build a section of freeway, only to reroute traffic a year later and dig it all up again? Why are all the lanes poorly marked, substandard width, winding, and in general, in poor repair? We've managed to build at least three complete freeway systems in Austin in the same amount of time that compromise more roadway milage and they're completely complete -- no bullshit. Of course, now that I look around on Google Maps, I can find no evidence of the construction. I guess that's part of the issue of virtually "driving" 75 miles of road and the fact that the really bad construction tends to be limited to segments a couple of miles long. I will say that even driving through there just a few months ago, my girlfriend commented, "is construction always this bad through here?" and was astounded when I told her it had been since before I got my driver's license. [edit] Ah, here we go. These are pretty normal conditions for this stretch of freeway. And this kind of crap is the stuff I've been seeing for nearly 20 years now. The patch of Baytown near the Chevron factory looked just like this for the better part of a decade, now they've just moved downstream a few miles. einTier fucked around with this message at 23:34 on Oct 7, 2009 |
|
#
?
Oct 7, 2009 23:27
|
|
|
nm posted:This hasn't stopped anything in Minneapolis Rather scary, isn't it? How do you feel about driving on roads when you know we can't afford to maintain them? einTier posted:What is going on here? Why do they build a section of freeway, only to reroute traffic a year later and dig it all up again? Why are all the lanes poorly marked, substandard width, winding, and in general, in poor repair? We've managed to build at least three complete freeway systems in Austin in the same amount of time that compromise more roadway milage and they're completely complete -- no bullshit. Every project is different, and I can't say anything about this one, as I've never heard of it before, but I can say that many projects go WAY over schedule. There are two bridges in Warren and Barrington, Rhode Island, each about 500 feet long. Way back in the mid-90s, they were deemed unsafe, and temporary bridges were built for both. Well, first, they neglected to put any real guard rail on the temporary bridges. Someone drove a bit too fast and plunged right over the edge, into the water. Oops! So they put up some heavy wood blocks and anchored them to the deck. Next up, they looked for a contractor. Then, they tried to get the new bridge built, hitting all sorts of old masonry and piers underwater, massive geotechnical and logistic problems, and so on and so on. It wasn't until 3 years ago, a decade after the bridges were closed, that the substructures even broke the water surface. Now, in 2009, the new bridges are mostly completed. I'm sure that, if a couple small bridges can take 15 years to replace, 75 miles of freeway could easily take 20+. They must have hit some really major problems (contractor going out of business, lack of proper supplies, huge right-of-way impacts and ensuing eminent domain battles) to cause it to last this long. Remember, when a problem arises, the contractor won't clean up the work zone and let people drive into the massive hole they just dug in the shoulder. They'll leave that work zone up for years.
|
|
#
?
Oct 8, 2009 01:44
|
|
|
einTier posted:Wow. Great thread. Took me two full days to read through it all. The Beaumont TxDOT office doesn't have the same incentive / penalty packages included in construction projects as the Houston office. Also, remember floods in 1994 when the gas pipeline cracked and exploded, burning the bridge over the San Jacinto River to a nice crispy structure? That was fun. I-45 outside Dallas has been like that for years. I went up that way once during college and again last year (~5 year difference) and they still had it screwed up. Nexis fucked around with this message at 02:31 on Oct 8, 2009 |
|
#
?
Oct 8, 2009 02:28
|
|
|
Nexis posted:The Beaumont TxDOT office doesn't have the same incentive / penalty packages included in construction projects as the Houston office. Also, remember floods in 1994 when the gas pipeline cracked and exploded, burning the bridge over the San Jacinto River to a nice crispy structure? That was fun. Cichlidae posted:
Rereading my comment, it appears I'm really pissed about it, when I'm really not. Just curious, I guess. I only travel that section of road once or twice a year now, so it's not enough to aggravate me anymore. It's just kind of a general "really, you guys can't get your poo poo together in all this time?" Most of the land is empty enough to have virtually unused feeders and the soil and topography aren't particularly challenging.
|
|
#
?
Oct 8, 2009 02:47
|
|
|
einTier posted:Thanks for that. I never considered that maybe the contractors went out of business and got sued and maybe there was a long backlog in court. I think what surprised me most was that areas that seemed complete would suddenly be dug up and redone just a year or two later for no apparent reason -- these aren't bridges, the right of way has already been decided, there was no uneven pavement, just apparently perfectly good freeway ripped up and new stuff put down. It's really frustrating to see them tear up a seemingly good piece of pavement, but it usually indicates that they (or the previous contractor) severely hosed something up. I'm not sure if I mentioned it in this thread, but in one of our projects, the contractor installed the catch basins upside-down, and the inspector didn't catch it. After both had been let go and heartily sued, the new contractor had to rip them out and replace them, a very long and frustrating process. It was made even worse by the fact that we couldn't tell the public WHY they were doing it, because of the ongoing lawsuit.
|
|
#
?
Oct 8, 2009 03:01
|
|
|
Cichlidae posted:It's really frustrating to see them tear up a seemingly good piece of pavement, but it usually indicates that they (or the previous contractor) severely hosed something up. I'm not sure if I mentioned it in this thread, but in one of our projects, the contractor installed the catch basins upside-down, and the inspector didn't catch it. After both had been let go and heartily sued, the new contractor had to rip them out and replace them, a very long and frustrating process. It was made even worse by the fact that we couldn't tell the public WHY they were doing it, because of the ongoing lawsuit. In a similar story not related to roads. There was a new mall built in our area without any electrical or plumbing coduit/wire/piping put in because the general contractor was never given the final plans, the only set he had were marked draft and their contract stated they couldn't use draft plans. So they completed the mall sans electric/plumbing. Who the hell thought that was a good idea?
|
|
#
?
Oct 8, 2009 18:54
|
|
|
Hey, Cichlidae, do you have a graphic of map of what the new 95 / 195 Interchange is going to look like when it's all done? I'm curious, since I live so close that I either see it or drive through it every single day. Right now they're working like gangbusters, and it looks different almost every day.
|
|
#
?
Oct 12, 2009 02:13
|
|
|
Nebulis01 posted:In a similar story not related to roads. There was a new mall built in our area without any electrical or plumbing coduit/wire/piping put in because the general contractor was never given the final plans, the only set he had were marked draft and their contract stated they couldn't use draft plans. So they completed the mall sans electric/plumbing. That's really really awesome. Did the contractor get his rear end sued to hell and back? If a contractor tries something that dumb with our signals, they can get in loads of trouble / banned from doing work. Besides, I think someone doing something that dumb might actually violate engineering / building codes in the state.
|
|
#
?
Oct 12, 2009 02:41
|
|
|
Pagan posted:Hey, Cichlidae, do you have a graphic of map of what the new 95 / 195 Interchange is going to look like when it's all done? I'm curious, since I live so close that I either see it or drive through it every single day. Right now they're working like gangbusters, and it looks different almost every day. Sure thing. I actually did a minuscule amount of work on that project back when I worked at RIDOT. This map (PDF) shows the final interchange on the first page. It's a simple T-interchange, with all the entrances and exits on I-95 from the right, instead of the hellish previous configuration. You'll even have enough time to get two lanes left on I-95 NB so you don't get stuck in the exit-only lanes for Broadway or US 6! I drive through there every time I go to Rhode Island so I can check on the progress. You'll notice that the new ramps are still rather bumpy, because they're paved with concrete. They should cover that up with smooth asphalt once the whole thing is ready.
|
|
#
?
Oct 12, 2009 04:29
|
|
|
Nexis posted:That's really really awesome. Did the contractor get his rear end sued to hell and back? If a contractor tries something that dumb with our signals, they can get in loads of trouble / banned from doing work. If a contractor uses plans that aren't stamped by an engineer (and therefore, not final), they're very much liable for the result. We have to stamp every little thing here, including signal plans, which is pretty awful when your signal plans include the timings. Every time I go out and revise timings in the field, I'm supposed to go back and draft up a signal revision, and that takes a lot of time. One thing I learned quickly here was not to let draft plans out without stamping "PRELIMINARY" all over the plan. On one project, I was designing a signal, and the utilities couldn't decide where they were going to relocate their poles. I just picked some random spots, because I needed to get the draft plan out and it wouldn't do to have it missing the poles. Well, Electrical wanted a copy, so I let them print one. Then they gave it to the Highways guy, and he made a copy for the Utilities guys, and they got REALLY pissed off at me. "We choose where the utility poles go, not you!" It doesn't stop there, though. Somehow (and I'm still not sure how), the plan got to the town architect, who ended up calling me up and asking why I was putting a pole on top of his decorative luminaire. I had to explain a few times that it was just a draft, definitely going to change, etc. It's a really frightening feeling when you realize something's so far out of your control.
|
|
#
?
Oct 12, 2009 04:38
|
|
|
Thanks for this thread. I was a CHE that always used to make fun of CivE (mostly because their department was about half the size of ours, and we always thrashed them in case races), but this thread is really interesting. I think it's been brought up before, but I just wanted to talk about lanes of through traffic that suddenly become parkable during specific times. I just moved to St Louis, and one of their moderately busy surface streets normally has two lanes and parking along the outside. On Sundays, however, the signs dictate that you're supposed to park at a 45 degree angle, with your back right wheel touching the curb. Of course, this cuts into the rightmost lane, so the two lane street becomes a one lane street. I also imagine that you need to block off the only usable lane of traffic to back into one of these spots, although I haven't seen it done yet. I never saw this kind of parking before where I grew up in California, so it definitely surprised me when I first saw it. Mr. Traffic Engineer, what possible reason could they have for this?
|
|
#
?
Oct 12, 2009 04:43
|
|
|
Lobster Maneuver posted:Thanks for this thread. I was a CHE that always used to make fun of CivE (mostly because their department was about half the size of ours, and we always thrashed them in case races), but this thread is really interesting. Volumes on Sunday are lower than any other day of the week. The second lane isn't needed, and, presumably, there are enough gaps for people to pull in and out of the parking spots. If you're not using that second lane for traffic, why not use it for parking? On-street parking is a relatively effective means of traffic calming because the narrower lanes and uncertainty force drivers to slow down. What you're describing was discussed earlier in the thread, and it's called back-in pull-out parking. It's safer than the alternatives, because the driver has a full view of traffic when performing the backing maneuver and the door doesn't open into traffic. My coworkers are quite skeptical, but that's not really important, because Connecticut DOT doesn't put parking on state routes; we only allow towns to do it with an encroachment permit. As to parking with a wheel against the curb, though, I'd never do that. My car is pretty low, and getting its bumper over any curb involves some rather unpleasant scraping and grinding.
|
|
#
?
Oct 12, 2009 05:07
|
|
|
Cichlidae, I can't remember now what the rubber sensor strips are called that they lay in the road to record the number of passing cars along with their speeds. But I'll assume you know what I'm talking about. Is there any rule as to where they're supposed to lay these out? I suppose it might depend on what they're trying to measure, but they just put some down near my house in what appears to be a really stupid place unless they're intentionally trying to get inaccurate data. They put them right before (or after, depending on your direction) an intersection where there's a turn onto a side street. So some small but not insignificant percentage of people are going to drive over the strips just before or just after turning into/from the side street, meaning they're going maybe 20-25 MPH as opposed to the 35-45 MPH other cars are probably going (speed limit is 35). The only reason I could see them wanting to place the sensors in that particular spot is to artificially inflate the number of "slow" drivers in their results, to bring the average down (speed limits must be set at the 85th percentile). There's plenty of room for them to have put them a little farther down the road without any side-street issues.
|
|
#
?
Oct 12, 2009 05:09
|
|
|
Choadmaster posted:Cichlidae, I can't remember now what the rubber sensor strips are called that they lay in the road to record the number of passing cars along with their speeds. But I'll assume you know what I'm talking about. They're pneumatic tubes. quote:Is there any rule as to where they're supposed to lay these out? I suppose it might depend on what they're trying to measure, but they just put some down near my house in what appears to be a really stupid place unless they're intentionally trying to get inaccurate data. They put them right before (or after, depending on your direction) an intersection where there's a turn onto a side street. So some small but not insignificant percentage of people are going to drive over the strips just before or just after turning into/from the side street, meaning they're going maybe 20-25 MPH as opposed to the 35-45 MPH other cars are probably going (speed limit is 35). Well, here's how it works. I want to do a signal warrant analysis or whatever. I make a sketch of the subject area, and draw some lines across the roads. That goes down to the counts department, and they lay out the detectors in those locations and get back to me in a couple months. The locations usually depend on having a nearby utility pole or tree they can chain the count box to, otherwise it'll get stolen. No, I don't know where someone would fence a $200 count box, but that won't stop people from trying. While it makes sense to put them in the middle of a stretch of road for a speed survey (and what you're saying could very well be true if that's the case), for a set of counts, the count stations should be as close to the intersection as possible to minimize the effect of people entering/exiting driveways. I wouldn't expect sinister motives, though. The guys who go out there at 4 a.m. and set up the count boxes don't care one way or another what the counts end up being, they just want to do it quickly and get home.
|
|
#
?
Oct 12, 2009 05:16
|
|
|
There aren't any driveways along the stretch where they are so that isn't an issue. There's also convenient utility poles all along the stretch, also. However I just noticed they're right next to the "Entering the City" sign, so maybe they just stuck them right on the border to count cars coming into town via this route. Which would be pretty stupid, because that'll also count anyone coming that way out of the side street, and the side street is also inside the city limits (border makes a 90 degree turn there). I suppose it'll just have to be a mystery. On an unrelated note, I was driving up a 1-way street through downtown today and there's about 8 lights in a row that used to be perfectly timed so you'd never have to stop, but today they were all the gently caress over the place. Maybe 3 of the 8 were still on the original timing, but they were nonconsecutive so while I got held up by one of the now hosed-up signals I could only look longingly down the street at the next intersection with the inviting green light... This had better be temporary. It really makes me appreciate the work you guys do (knowing how bad it is without your careful tuning). Signal setups and such used to be awesome in this town, and then the traffic engineer died of a heart attack in his office while working overtime a couple years ago and I swear things have been slowly going to poo poo. Please keep yourself healthy!
|
|
#
?
Oct 12, 2009 06:23
|
|
|
Choadmaster posted:There aren't any driveways along the stretch where they are so that isn't an issue. There's also convenient utility poles all along the stretch, also. We also do border counts on each state road that crosses town boundaries, so that'd be an excellent explanation. quote:On an unrelated note, I was driving up a 1-way street through downtown today and there's about 8 lights in a row that used to be perfectly timed so you'd never have to stop, but today they were all the gently caress over the place. Maybe 3 of the 8 were still on the original timing, but they were nonconsecutive so while I got held up by one of the now hosed-up signals I could only look longingly down the street at the next intersection with the inviting green light... This had better be temporary. It doesn't take much to knock a coordinated system out of whack. One pedestrian calls a ped phase, and then that signal has to double-cycle. It may be several minutes before it can catch back up with the rest. Having even one signal out of synch can make you stop two or more times, so it can seem like the rest of the system is broken as well. quote:It really makes me appreciate the work you guys do (knowing how bad it is without your careful tuning). Signal setups and such used to be awesome in this town, and then the traffic engineer died of a heart attack in his office while working overtime a couple years ago and I swear things have been slowly going to poo poo. Please keep yourself healthy! Boy, that's not good. I'm working 10 hours of OT this week because of a couple projects that were dumped on me at the last minute. I also have heart problems from all the stress (had to stop drinking coffee because of it). Let's hope I don't keel over at work! I need to make it to my wedding.
|
|
#
?
Oct 12, 2009 15:37
|
|
|
If you thought cloverleaf's lent themselves to weaving, you haven't seen anything yet. May I introduce you to a juggernaut of 60's urban planning, the Coventry Ring Road: Looks quite benign from up here doesn't it? Originally designed with every junction as a roundabout, some bright spark at the planning office suddenly decided that the road could be grade seperated along it's massive 2 mile length. That's eight grade seperated junctions on just less than 2 miles of road, or a junction every 400m on average. Here's a closer look at my favourite junction:  Being generous, that's about 10 car lengths for everybody to get on and off the road. Notice also how traffic coming off the ring road is already in a feeder lane before traffic trying to get onto the road has even thought about merging, and there's another junction waiting just a few hundred meters further along. Google's plane chose a quiet time of day to fly over, walking past any junction on this road at rush hour is a giant example of Brownian motion. Traffic coming onto the road tends to jump all the way across into the outside lane, while traffic coming off the road has to squabble with traffic in the far left lane of the ramp to get in position for the roundabout at the bottom. The first time I drove on this road I made the mistake of driving in the left hand lane down the on-ramp and physically couldn't get onto the ring road, you have to disregard the rules of every other road in the country and keep right as much as you can. It's so odd the police have put a video on YouTube explaining how to drive on it: http://www.youtube.com/watch?v=5IOKcrQJnjs Yet despite all this, it works quite well. I can drive from my partner's house to my student house and spend all of 5 minutes on residential roads, the rest of the journey is on glorious motorways and dual carriageways. The speed limit in 'only' 40, although lots of the time even that feels terrifyingly quick. There's several elevation changes and sharp turns along the length of the road, and some of the slip roads are even worse, twisting and diving around like a contortionist's arm caught in some heavy machinery. Still, if the road wasn't there all the traffic that uses it would have to fart it's way through Coventry city centre, which is probably an even more terrifying prospect.
|
|
#
?
Oct 12, 2009 16:40
|
|
|
jammyozzy posted:If you thought cloverleaf's lent themselves to weaving, you haven't seen anything yet. May I introduce you to a juggernaut of 60's urban planning, the Coventry Ring Road: That video was great. If the police have to make a video explaining how to drive on a road, you know that it's going to be substandard. About the road itself, it looks like a very tight circle. Did it replace a wall around Coventry? That would certainly explain the sharp curves. I'll be sure to drive around it a couple times if I ever find myself over there. As an aside, it was amazing to me that, when the dual red/yellow signal went up, everyone's brake lights went off, but they didn't scoot into the intersection. If we did that here, by the time the light turned green, the first cars would already be halfway through the intersection. It certainly seemed to improve start-up times! We assume here that the first car passes the stop bar a full 4 seconds after the light turns green, and each subsequent car takes 2 seconds beyond that. In the video, it was more like 1.5 seconds for the first car and a second for each additional one. Impressive!
|
|
#
?
Oct 12, 2009 17:01
|
|
|
Nope, large parts of Coventry were destroyed during the Blitz, giving planners an almost clean slate to work with. England went ring road crazy for a couple of decades after the war, for example at one point London was supposed to have 4 concentric ring roads rather than the one and a half it has today. As for the red + yellow light phase, it's a really neat idea. I can be stopped at a red in neutral with the handbrake on, and then be in gear and rolling by the time the light has gone green. jammyozzy fucked around with this message at 17:12 on Oct 12, 2009 |
|
#
?
Oct 12, 2009 17:07
|
|
|
jammyozzy posted:Nope, large parts of Coventry were destroyed during the Blitz, giving planners an almost clean slate to work with. England went ring road crazy for a couple of decades after the war, for example at one point London was supposed to have 4 concentric ring roads rather than the one and a half it has today. I know this must sound terribly naïf, but many of my peers wish that our cities had suffered the same sort of bombardment here so we'd have some corridors for improvement. Obviously, a few freeways and a tidy urban center isn't justification for reducing a city to rubble, but traffic engineers 65 years removed from the carnage tend to see it that way.
|
|
#
?
Oct 12, 2009 17:15
|
|
|
Cichlidae posted:It doesn't take much to knock a coordinated system out of whack. One pedestrian calls a ped phase, and then that signal has to double-cycle. It may be several minutes before it can catch back up with the rest. Having even one signal out of synch can make you stop two or more times, so it can seem like the rest of the system is broken as well. None of our timed signals have walk buttons at the crosswalk. Pedestrians just have to wait for the timed signal like everyone else. I can't imagine a timed signal that could be overridden by pedestrians, it seems like it would pretty much always be out of sync!
|
|
#
?
Oct 12, 2009 22:49
|
|
|
Choadmaster posted:None of our timed signals have walk buttons at the crosswalk. Pedestrians just have to wait for the timed signal like everyone else. I can't imagine a timed signal that could be overridden by pedestrians, it seems like it would pretty much always be out of sync! Maybe it just broke. It's not uncommon to see a communication wire knocked out, or a loop broken. You should considering calling up whoever owns the road and letting them know if symptoms persist. In most cases, we have no other way of knowing if something breaks.
|
|
#
?
Oct 12, 2009 23:57
|
|
|
Who would you call to report broken signals or downed signs? The non-emergency number for the local PD, or is there usually a number for the DOT that you should call?
|
|
#
?
Oct 13, 2009 00:05
|
|
|
thelightguy posted:Who would you call to report broken signals or downed signs? The non-emergency number for the local PD, or is there usually a number for the DOT that you should call? The first step is to find out who owns the signal. If it's on a state road, it's probably a state-owned signal. Otherwise, it's county- or town-owned. Even if you guess wrong, someone will set you straight. I'd say the best number to call would be Maintenance, which should be pretty easy to find online. You could even call the DOT secretariat and ask whom you'd need to call about a broken signal. We're quite forthcoming and wouldn't mind directing you to the right person if you get a wrong number. If you called the police, they'd just redirect you to us anyway. They don't have any access to the inside of the signal box, just a little panel on the front that they can use to manually control it in emergencies.
|
|
#
?
Oct 13, 2009 00:24
|
|
|
Cichlidae posted:Maybe it just broke. It's not uncommon to see a communication wire knocked out, or a loop broken. You should considering calling up whoever owns the road and letting them know if symptoms persist. In most cases, we have no other way of knowing if something breaks. In a CBD (Central Business District) you generally do not have pushbuttons on the signals. In the city we had ~300 signals downtown, all 2 phase with peds. It generally is not worth installing pushbuttons since the signals aren't actuated anyway. Just bring the ped up every time the phase comes in. The other ones that do not have them are signals that were retrofitted from an electromechanical controller. Again, these were pretimed, and there was no way to actuate any of the vehicle movements or ped movements.
|
|
#
?
Oct 13, 2009 14:39
|
|
|
Nexis posted:In a CBD (Central Business District) you generally do not have pushbuttons on the signals. In the city we had ~300 signals downtown, all 2 phase with peds. It generally is not worth installing pushbuttons since the signals aren't actuated anyway. Just bring the ped up every time the phase comes in.
|
|
#
?
Oct 13, 2009 17:06
|
|
|
Ripper Swarm posted:They'd have to do it by mile, not time; I can't imagine the road rage people would give you if you managed to close a motorway and started costing them serious money! I imagine pricing would be dependant on type of road/time of day so being on a major motorway at 9am would be most expensive and being on a rural back road at 3am would be practically free. That would mean if you do the same route each weekday, it would cost you the same amount each day. On the express lanes on I-15 in San Diego they do congestion-based pricing per mile. It starts out at $0.80 for the entire 16 (soon to be 20) mile stretch but ranges up to $18 before shutting it down to non-HOV traffic based on traffic volumes. If you enter when it's $0.80 you only pay $0.80 for the entire trip regardless of traffic volumes.
|
|
#
?
Oct 13, 2009 18:03
|
|
|
Nexis posted:In a CBD (Central Business District) you generally do not have pushbuttons on the signals. In the city we had ~300 signals downtown, all 2 phase with peds. It generally is not worth installing pushbuttons since the signals aren't actuated anyway. Just bring the ped up every time the phase comes in. We do ped phases quite differently in Connecticut. Our previous policy was to put ped buttons and ramps at every signal where ped crossing wasn't explicitly forbidden. Recently, we stopped building ramps where there weren't already sidewalks, and we can (very rarely) omit a ped button entirely. Unlike most states, Connecticut DOT doesn't put in a pedestrian signal head in concurrent walk phases, only in dedicated ped phases, which, while common in urban areas, certainly don't come in every cycle. Most of the peds don't even hit the buttons and just cross when they see a gap. Of course, then the cities have their own standards, and people get quite confused. There's very little we can do about that. As it stands, when a ped presses the button on a concurrent phase, he can't tell if he's extended the phase. I nearly got run over once because the button itself had broken, and the phase didn't extend, trapping me in the median of a 5-lane arterial. Ideally, we'd have ped heads for even concurrent phases, but people here already expect that a ped head means an exclusive phase, so we can't just switch over. dexter posted:On the express lanes on I-15 in San Diego they do congestion-based pricing per mile. It starts out at $0.80 for the entire 16 (soon to be 20) mile stretch but ranges up to $18 before shutting it down to non-HOV traffic based on traffic volumes. If you enter when it's $0.80 you only pay $0.80 for the entire trip regardless of traffic volumes. That seems like a very reasonable and expedient way to do it, provided that price is visibly displayed as you enter.
|
|
#
?
Oct 13, 2009 23:18
|
|
|
|
| # ? Apr 28, 2024 12:04 |
|
|
Socket Ryanist posted:What about nighttime? Nope, pretimed. Peds come up every cycle.
|
|
#
?
Oct 14, 2009 00:05
|
|