I'm sure everyone can think of a road that is full of closely spaced traffic signals that seem to stop you at every light. For me it's Jefferson Ave from downtown Detroit to the Grosse Point Park border. It's a 6.4 mile stretch that has just under 40 traffic signals. The signals run a fixed time and cycles regardless of detection. You will notice a few blatant red light runners that treat the red indication as a 4-way stop.
EB PM drive (Heavy direction):
WB PM drive (Light direction):
Sherman Way through the S.F. Valley
US-441 through Orlando. 126 traffic lights. I caught precisely 6 greens.
I've never been to NYC and watching Cash Cab is the closest i've come to seeing what traffic is like in Manhattan. Does anyone know the basic strategy the city uses to time their closely spaced lights especially a road like Park Ave that has two way traffic and signals every 250 feet?
US 30 between the Parkway East and Greensburg
US 280 between the Red Mountain Expressway and Doug Baker Blvd in Birmingham
Honorable Mention:
US 31 between the Red Mountain Expressway and I-65 in Alabaster.
Any major street in Chicago (I've personally only been on Sheridan Rd., but I've heard about the poor timing on Chicago traffic lights)
US-30 in Indiana doesn't have lights closely spaced (except in Warsaw), but there is an unnecessary amount of them.
Quote from: pianocello on August 15, 2011, 08:15:56 PM
Any major street in Chicago (I've personally only been on Sheridan Rd., but I've heard about the poor timing on Chicago traffic lights)
More like all of Chicagoland; the only routes that seem to have any sort of coordination are IL 132 between the Tri-State and US 45 (but not EB in the afternoon), and Lake Cook Road between the Tri-State and the IL 53 freeway.
Actually, I think it would be easier to list routes with coordinated closely space traffic signals than those that are not coordinated.
Quote from: tradephoric on August 15, 2011, 11:20:39 AM
I've never been to NYC and watching Cash Cab is the closest i've come to seeing what traffic is like in Manhattan. Does anyone know the basic strategy the city uses to time their closely spaced lights especially a road like Park Ave that has two way traffic and signals every 250 feet?
Well, the one way avenues are nicely timed to have the lights progress up the block at about 30 MPH (the speed limit). And indeed, if traffic permits, you can expect to drive 20, 30, even 40 blocks up 1st Ave without hitting a red light.
Park Avenue and other two-way avenues, naturally, do not and cannot have such convenient light timing. There you will hit a red light every 5-10 blocks because, while the greens do at least seem to cluster together, they can't be made to progress with traffic since traffic goes both ways. I don't know what the precise strategy is. But I do know that NYC traffic signals are controlled by boxes at the site of the signal itself (some of which are mechanical - you can hear parts click and clank in there as the light changes!). They don't have a central computer controlling things. So, whatever coordination there is between signals is all still done the old-fashioned way: by having guys go out and set the up one by one onsite.
Broadmoor Ave between 28th St and M-6 in Kentwood has lights that are somewhat synced.
IL-59 between IL-56 and US-30 has 30 traffic lights. Also, IL-64 in St. Charles has 19 within a 5.6 mile stretch.
I've been having fun looking up all the roads on Google Earth that everyone is mentioning. If anyone is interested i set up a Google KMZ file comparing the routes with placemarks added at all the intersections along the route:
http://www.mediafire.com/?b262r5cm6j0puky (http://www.mediafire.com/?b262r5cm6j0puky)
I think driving Sherman Way would get me cursing the most as there appears to be a lot of major 4 phase intersections along the stretch. US-280 in Birmingham would be a prime candidate to convert to a superstreet. Lots of ROW along the stretch and the lights seem to serve mostly businesses/drives (resulting in low cross street through traffic).
ANY central business district is going to have traffic lights at nearly every block. I know Chicago and Milwaukee do for sure. I bet most of NYC - especially Manhattan (midtown and lower in particular) have such.
A spot with close-proximity signals that has crap for timing would be WIS 52 at 17th and 18th aves and 18/Stewart Aves in Wausau, WI. 250ft between each signal.
Quote from: Master son on August 16, 2011, 01:36:56 PM
ANY central business district is going to have traffic lights at nearly every block. I know Chicago and Milwaukee do for sure. I bet most of NYC - especially Manhattan (midtown and lower in particular) have such.
A spot with close-proximity signals that has crap for timing would be WIS 52 at 17th and 18th aves and 18/Stewart Aves in Wausau, WI. 250ft between each signal.
Pittsburg, Kan. Traffic lights
every block from 3rd to 10th on Broadway but only the one at 4th (K-126) is a modern set up. All the others still only have the lights on posts on the sidewalk. If they hadn't made them bigger a couple of years ago, some of them would be imposssible to see. Also lights on four consecutive blocks if you're on 4th (Walnut-Pine-Broadway-Locust).
Joplin has lights on each block of Main from 2nd to 7th, on each block of 7th from Wall to Virginia, each block of 4th from Wall to Virginia and each block of 2nd from Wall to Pennsylvania. So that's 17 traffic lights in, what, 19 square blocks (Virginia and 2nd don't meet, IIRC)?
Quote from: Master son on August 16, 2011, 01:36:56 PM
ANY central business district is going to have traffic lights at nearly every block. I know Chicago and Milwaukee do for sure. I bet most of NYC - especially Manhattan (midtown and lower in particular) have such.
Manhattan has sometimes been referred to as "the land of no stop signs". This obviously isn't literally true, but they
are rare. The grid system is such that three-way intersections exist only as anomalies, and basically any four-way intersection in Manhattan is going to have a signal (although, counterexamples
do exist (http://maps.google.com/?ll=40.867834,-73.923612&spn=0.008584,0.021136&z=16&vpsrc=6&layer=c&cbll=40.867736,-73.92389&panoid=t6b3Ko-X4cKYH5fh2BT2pg&cbp=12,74.07,,0,5.21)).
The outer boroughs are a different story. Plenty of unsignalized intersections there.
Quote from: Duke87 on August 15, 2011, 09:41:01 PM
Well, the one way avenues are nicely timed to have the lights progress up the block at about 30 MPH (the speed limit). And indeed, if traffic permits, you can expect to drive 20, 30, even 40 blocks up 1st Ave without hitting a red light.
Park Avenue and other two-way avenues, naturally, do not and cannot have such convenient light timing. There you will hit a red light every 5-10 blocks because, while the greens do at least seem to cluster together, they can't be made to progress with traffic since traffic goes both ways. I don't know what the precise strategy is. But I do know that NYC traffic signals are controlled by boxes at the site of the signal itself (some of which are mechanical - you can hear parts click and clank in there as the light changes!). They don't have a central computer controlling things. So, whatever coordination there is between signals is all still done the old-fashioned way: by having guys go out and set the up one by one onsite.
A technical note: Most, if not all, jurisdictions have signal controller cabinets at each intersection (or inbetween two intersections, in the case of some diamond interchanges and other closely-spaced intersections where it is desired to operate the two intersections as one unit for efficiency reasons). There are still some older mechanical signal controller units, but more and more controllers are computerized. For newer controllers, you will typically see a large rectangular cabinet which will hold the actual signal controller computer, a conflict monitoring device, and electrical control relays for each signal phase, as well as other items such as a TV monitor (for setting up and viewing video detection feeds, if used), manual override switches, and battery backups (often seen at SPUIs and signals near train crossings. Given the necessary interconnect structure, signal controllers can be on a centralized system where updates can be performed remotely and some communication between adjacent signals can be achieved. However, unless its a small network or a more sophisticated system is installed (like one with live updating and adaption based on real-time volume counts), the operation of each signal is generally done from the onsite controller and not a central computer.
With that said, it IS possible to achieve green progression on two-way streets. Some major cities, such as Las Vegas, do this regularly--in fact, there is regional agency tasked with this and other traffic improvement measures. Achieving decent two-way progression bands is not exactly easy, though. It does become easier when the intersecting streets are evenly spaced, major intersections are a bit more spread out, and you have left turn phases to add in--I believe the last two are not the case in NYC. However, even without those traits, it is possible to do some coordination to get a good progression band in one direction, but that might come at the cost of progression breakdown in the opposing direction.
Quote from: roadfro on August 16, 2011, 10:29:38 PMIt does become easier when the intersecting streets are evenly spaced, major intersections are a bit more spread out, and you have left turn phases to add in--I believe the last two are not the case in NYC.
you are correct. a lot of consecutive streets are given equal "major" importance - and the absence of left-turn protection is so monumental that driving in NYC (especially Manhattan) requires you to learn several behaviors which are technically illegal, the most important being that in order to make a turn, you will have to queue up, and then any queue lined up to turn will proceed through the intersection upon yellow, upon red, upon red, upon red, upon red...
I have made my left turn over 5-6 seconds after the light turned red, because that is the only way I will get through - and if I don't, the driver behind me will ride my bumper and honk! so long as there is a steady stream of traffic making the turn, it is treated as an implicit "funeral procession", with the lead car validating the turn of all the latter ones.
and yes, this is true for right turn as well. no, there is no major quantity of "no right turn on red" law - but the sheer amount of pedestrian traffic makes a right turn on green virtually impossible in many places.
if you ever want to have a fun go at life ... try driving Manhattan, on a slush-filled February afternoon, in a stick-shift '89 Escort!
(another rule of NYC driving is that yes, you are allowed to double- and even triple-park. the law may be the law, but it takes 20 minutes to call a tow truck; so don't be surprised to see delivery vehicles, as well as ordinary passenger cars, parked well into the right of way. It is, simply, the lay of the land, and therefore your responsibility to maneuver around them.)
Quote from: roadfro on August 16, 2011, 10:29:38 PMGiven the necessary interconnect structure, signal controllers can be on a centralized system where updates can be performed remotely and some communication between adjacent signals can be achieved. However, unless its a small network or a more sophisticated system is installed (like one with live updating and adaption based on real-time volume counts), the operation of each signal is generally done from the onsite controller and not a central computer.
The city of Stamford, CT has its signals all wired together with fiber optics and controlled by a central computer. There are onsite boxes, but those only take over in case of loss of communication with the central computer in City Hall.
Quote from: agentsteel53 on August 16, 2011, 10:57:39 PM
Quote from: roadfro on August 16, 2011, 10:29:38 PMIt does become easier when the intersecting streets are evenly spaced, major intersections are a bit more spread out, and you have left turn phases to add in--I believe the last two are not the case in NYC.
you are correct. a lot of consecutive streets are given equal "major" importance - and the absence of left-turn protection is so monumental that driving in NYC (especially Manhattan) requires you to learn several behaviors which are technically illegal, the most important being that in order to make a turn, you will have to queue up, and then any queue lined up to turn will proceed through the intersection upon yellow, upon red, upon red, upon red, upon red...
Turn signals used to be unheard of in Manhattan but they have been popping up in recent years. The thing of it is, most streets in Manhattan are one way... it isn't oncoming traffic that left turn protection is needed from, it's pedestrians. Only in Manhattan will you find dedicated turn signals at an intersection between two one-way streets.
Of course, just because you have a green arrow, doesn't mean you can go... again, pedestrians.
As for proceeding on red, look out... you'll get your picture taken if you do it at the wrong intersection. And unlike in other places that have red light cameras, in New York most of them do not have signs warning of their presence. You just get "within NYC red lights photo enforced" at the city line and from there you're in a minefield.
^^ So I take it that Manhattan doesn't have the equivalent of the Lincoln Park (http://en.wikipedia.org/wiki/Lincoln_Towing_Service) Pirates (http://www.youtube.com/watch?v=389Rk1jzPMk). :colorful:
Quote from: Duke87 on August 17, 2011, 07:54:13 PM
As for proceeding on red, look out... you'll get your picture taken if you do it at the wrong intersection. And unlike in other places that have red light cameras, in New York most of them do not have signs warning of their presence. You just get "within NYC red lights photo enforced" at the city line and from there you're in a minefield.
Are the cameras very visible, if you know what to look for?
Be well,
Bryant
Quote from: Duke87 on August 17, 2011, 07:54:13 PM
As for proceeding on red, look out... you'll get your picture taken if you do it at the wrong intersection.
I think the rule is "don't be the first one to try it" - i.e. the locals seem to know which ones are okay to go through as a queue, and which are not.
I don't see why anyone would want to drive in NYC anyway. We're talking about the most transit rich city in America. There is no way in hell I would deal with NYC's tiny streets, subpar freeways, and relentless traffic.
Quote from: Riverside Frwy on August 17, 2011, 09:56:08 PM
I don't see why anyone would want to drive in NYC anyway. We're talking about the most transit rich city in America. There is no way in hell I would deal with NYC's tiny streets, subpar freeways, and relentless traffic.
Yeah, dont u wish things were that good in SoCal lol
Quote from: Riverside Frwy on August 17, 2011, 09:56:08 PM
I don't see why any normal person would want to drive in NYC anyway. We're talking about the most transit rich city in America. There is no way in hell I would deal with NYC's tiny streets, subpar freeways, and relentless traffic.
Fixed it. I can see driving in NYC once to clinch highways... can't exactly avoid local streets if you want to clinch I-78, I-478, or I-495. Not looking forward to if/when I clinch the NYC interstates.
Quote from: allniter89 on August 17, 2011, 10:07:07 PM
Quote from: Riverside Frwy on August 17, 2011, 09:56:08 PM
I don't see why anyone would want to drive in NYC anyway. We're talking about the most transit rich city in America. There is no way in hell I would deal with NYC's tiny streets, subpar freeways, and relentless traffic.
Yeah, dont u wish things were that good in SoCal lol
The geography of L.A. is the reason there can never be such an extensive subway system. Besides, the city was designed around the automobile, unlike the East Coast cities that long ago had other transit networks that didn't require automobiles.
there's three separate signallised junctions between here and the white building (http://maps.google.co.uk/?ll=50.908523,-1.408315&spn=0.000003,0.008256&z=18&vpsrc=6&layer=c&cbll=50.908463,-1.408282&panoid=T-LytOFcz8GiJ_dtP-PyiQ&cbp=12,347.76,,0,11.23)
...and at the white building there's three in view heading round (http://maps.google.co.uk/?ll=50.909626,-1.408637&spn=0.000003,0.008256&z=18&vpsrc=6&layer=c&cbll=50.909696,-1.408488&panoid=964xIZ-uhz8t3w9X8QsDEg&cbp=12,69.01,,1,0.22) - there's actually a shocking large 100yrd gap between lights!
and the first picture is at the other end of the building from here (http://maps.google.co.uk/?ll=50.906636,-1.406695&spn=0.000003,0.008256&z=18&vpsrc=6&layer=c&cbll=50.906557,-1.406627&panoid=kyEKUKuMNkaAfYIezoyAkA&cbp=12,321.74,,0,1.23), where there's two different sets of lights in quick succession. Just behind is a pelican crossing (oddly not synched with the rest of the lights - which have been computer controlled throughout the city for years), so another set of lights.
In half a mile, there are 9 sets of lights, 8 of which are road junctions (to Western Esplanade/from Civic Centre Road, from Western Esplanade/to Civic Centre Road, West Park Road/Commercial Road, Commercial Road, Devonshire Road, Grosvenor Square, Bedford Place, Above Bar Street/London Road), one a pedestrian crossing. They also come in threes - three clusters of three lights in ~450ft, with ~500ft gaps between those clusters.
There used to be two sets of lights here (http://maps.google.co.uk/maps?hl=en&ll=50.937956,-1.39735&spn=0.000002,0.004128&mra=mr&doflg=ptm&z=19&vpsrc=6&layer=c&cbll=50.937969,-1.397164&panoid=ys5YZHXU4tM60p5MuhoLJA&cbp=12,59.62,,0,5.88) - one for Dahlia Road (and a cycle path), the other for University Road. They stopped up Dahlia Road (other than for cyclists) and turned it into one big junction with a Toucan crossing for the cyclists going up Dahlia Road. The distance between the two junctions was about 15ft. This might be the overall winner.
Bare in mind that Southampton is the city with the most signallised junctions per head in Europe and has, as the pioneer (in Europe, at least) of computer-controlled road movements, using ROMANSE, has aggressively pursued a campaign of using traffic signals at every opportunity it can, often at junctions where it would be a simple T-junction with a Give Way elsewhere in Britain, given the traffic levels. I'm surprised that the Mayflower Roundabout (http://www.sabre-roads.org.uk/wiki/index.php?title=Mayflower_Roundabout) is still a roundabout!
Quote from: Bryant5493 on August 17, 2011, 08:23:16 PM
Quote from: Duke87 on August 17, 2011, 07:54:13 PM
As for proceeding on red, look out... you'll get your picture taken if you do it at the wrong intersection. And unlike in other places that have red light cameras, in New York most of them do not have signs warning of their presence. You just get "within NYC red lights photo enforced" at the city line and from there you're in a minefield.
Are the cameras very visible, if you know what to look for?
Their look is distinct, but no, they are not easy to spot. They are, after all, positioned to take pictures from behind. They're thus a lot easier to spot when you're going the opposite direction from them.
Quote from: Riverside Frwy on August 17, 2011, 09:56:08 PM
I don't see why anyone would want to drive in NYC anyway. We're talking about the most transit rich city in America. There is no way in hell I would deal with NYC's tiny streets, subpar freeways, and relentless traffic.
Some parts of the city are more car friendly than others. Driving into Manhattan I wouldn't do not on account of traffic but on account of parking is damn expensive and every garage has valets (I refuse to hand my keys to a valet). The exception is if it's a drive-by: only stopping briefly to drop someone off or pick someone up. Then the parking issue is a non-issue.
That said, I would qualify the statement about driving versus transit as such: tranist makes sense for getting around within the city, and it makes sense for heading from outside the city into Manhattan. But if one wants to get from Connecticut to The Bronx or Queens, then driving makes the most sense. The Bronx is particularly easy to get into and out of by car.
As for the other problems, subpar freeways aren't a big deal if you're used to them, and traffic isn't a huge issue either if you know what spots to avoid and how to avoid them.
And then there's timing. The Gowanus/BQE (I-278) may be notorious for traffic, but I've managed to do 80 mph from the Verazanno to the Triborough slowing down only for curves and to go around people... at about 1 AM Sunday morning. :sombrero:
I remember when I used to drive to New York every other weekend or so, I'd park in Brooklyn where a friend of mine lived and parking was relatively easy to find, and we'd take public transportation and the occasional cab.
the one time I remember finding parking in Manhattan, it was in SoHo and I parked right in front of my other friend's house after searching for parking for precisely 2 seconds. I figure I'd never be able to do that again!
Quote from: Duke87 on August 17, 2011, 07:54:13 PM
As for proceeding on red, look out... you'll get your picture taken if you do it at the wrong intersection. And unlike in other places that have red light cameras, in New York most of them do not have signs warning of their presence. You just get "within NYC red lights photo enforced" at the city line and from there you're in a minefield.
One must also remember that RTOR is prohibited in NYC...possibly the only major jurisdiction in the country where it's still not allowed.
Quote from: SidS1045 on August 21, 2011, 07:32:51 AM
Quote from: Duke87 on August 17, 2011, 07:54:13 PM
As for proceeding on red, look out... you'll get your picture taken if you do it at the wrong intersection. And unlike in other places that have red light cameras, in New York most of them do not have signs warning of their presence. You just get "within NYC red lights photo enforced" at the city line and from there you're in a minefield.
One must also remember that RTOR is prohibited in NYC...possibly the only major jurisdiction in the country where it's still not allowed.
I've been trying to figure out the reasoning behind that.
This thread reminded me of a video i watched on youtube about a city in England that shut out the lights at a bunch of closely spaced traffic signals in the heart of the city:
A previous poster mentioned the city of Southampton uses an adaptive system known as ROMANCE. I went to Southhampton's ROMANCE website and found a cool link that gives you travel times on some main corridors through the city. Does the city use the data collected from the intersections to create this map and estimate the travel times along the signalized corridor?
http://www.southampton.romanse.org.uk/ (http://www.southampton.romanse.org.uk/)
(you have to click on 'Journey Times' tab in the legend)
I think it's ANPR (auto number plate recognition) and Traffic Cameras, though I'd imagine that they probably used to do with clever calculations with traffic lights and guesses at traffic speeds, but ANPR would be easier and more reliable.
Quote from: Riverside Frwy on August 21, 2011, 11:19:33 AM
Quote from: SidS1045 on August 21, 2011, 07:32:51 AM
One must also remember that RTOR is prohibited in NYC...possibly the only major jurisdiction in the country where it's still not allowed.
I've been trying to figure out the reasoning behind that.
Because traffic conditions are such that it's rarely "safe" to make a right on red. And in circumstances where it is, they do have exceptions...
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fimg845.imageshack.us%2Fimg845%2F9964%2Fdscn4225web.jpg&hash=40c471264ec289179a29e867d29827bb5d869190)
Quote from: SidS1045 on August 21, 2011, 07:32:51 AM
Quote from: Duke87 on August 17, 2011, 07:54:13 PM
As for proceeding on red, look out... you'll get your picture taken if you do it at the wrong intersection. And unlike in other places that have red light cameras, in New York most of them do not have signs warning of their presence. You just get "within NYC red lights photo enforced" at the city line and from there you're in a minefield.
One must also remember that RTOR is prohibited in NYC...possibly the only major jurisdiction in the country where it's still not allowed.
Because of the large amount of traffic and the pedestrians, making the risk for an incident much higher.
Montreal has the same restriction.
Quote from: tradephoric on August 22, 2011, 10:08:14 AM
A previous poster mentioned the city of Southampton uses an adaptive system known as ROMANCE. I went to Southhampton's ROMANCE website and found a cool link that gives you travel times on some main corridors through the city. Does the city use the data collected from the intersections to create this map and estimate the travel times along the signalized corridor?
http://www.southampton.romanse.org.uk/ (http://www.southampton.romanse.org.uk/)
(you have to click on 'Journey Times' tab in the legend)
Quote from: english si on August 22, 2011, 01:27:00 PM
I think it's ANPR (auto number plate recognition) and Traffic Cameras, though I'd imagine that they probably used to do with clever calculations with traffic lights and guesses at traffic speeds, but ANPR would be easier and more reliable.
I would hazard a guess that there is some sort of sensors out on the roads that do the calculation for a given segment. It's a bit tricky to get a travel time to be fairly reliable on a surface road, especially when there's signals and many intersections or driveways present.
In Las Vegas, the FAST system has radar sensors set up approximately every 1/3 mile on the major freeways. These sensors can do vehicle counts, as well as figure out approximately how fast a vehicle is moving. Using the data from these sensors, an average speed over a third-mile segement can be obtained. These speed calcs are aggregated to display travel times on VMS devices, as well as produce a similar speed map on their website. Similar systems are used by other agencies, and the speed detectors can vary from the radar devices to microwave and even "old-fashioned" inductive loops in th pavement.
Oakland County (NW of Detroit) uses as adaptive traffic signals system known as SCATS to control over 630 signals. The county uses the degree of saturation at each intersection and uses that data to set up a rudimentary real time congestion map for the major surface streets throughout the county.
http://www.rcocweb.org/Pages/Real_Time_Traffic_Map.aspx (http://www.rcocweb.org/Pages/Real_Time_Traffic_Map.aspx)
(in the legend, click inside the mini county map for the congestion data to display)
The map only shows the spot congestion at each individual intersection but it assumes that the link between two congested intersections is going to be congested as well.
Quote from: roadfro on August 23, 2011, 06:49:01 AM
Quote from: tradephoric on August 22, 2011, 10:08:14 AM
A previous poster mentioned the city of Southampton uses an adaptive system known as ROMANCE. I went to Southhampton's ROMANCE website and found a cool link that gives you travel times on some main corridors through the city. Does the city use the data collected from the intersections to create this map and estimate the travel times along the signalized corridor?
http://www.southampton.romanse.org.uk/ (http://www.southampton.romanse.org.uk/)
(you have to click on 'Journey Times' tab in the legend)
Quote from: english si on August 22, 2011, 01:27:00 PM
I think it's ANPR (auto number plate recognition) and Traffic Cameras, though I'd imagine that they probably used to do with clever calculations with traffic lights and guesses at traffic speeds, but ANPR would be easier and more reliable.
I would hazard a guess that there is some sort of sensors out on the roads that do the calculation for a given segment. It's a bit tricky to get a travel time to be fairly reliable on a surface road, especially when there's signals and many intersections or driveways present.
As I said, ANPR would be more reliable than the complex calculations that other methods (radar sensors, induction loops, etc) would be for average speed. ANPR is also what they also use on the freeways in Great Britain for sites like Traffic England. Having some closed circuit visible light cameras and software that picks up number plates and then calculates the point-to-point time for number plates that appear on two cameras (and then ditches the number plate data, hopefully) would be the easiest and most accurate way, now the software exists to process the video (though it was invented in the 70s), to measure average speeds - especially if there are driveways and side turns and stuff.
Doing a bit of digging (though it hardly took any), ROMANSE does use ANPR for journey times. Traffic signals will use the induction loops (given they are all at junctions, it's not good for journey times as the speed data would be off) as they use SCOOT (http://www.scoot-utc.com/).
Quote from: english si on August 23, 2011, 06:18:55 PM
Quote from: roadfro on August 23, 2011, 06:49:01 AM
Quote from: tradephoric on August 22, 2011, 10:08:14 AM
A previous poster mentioned the city of Southampton uses an adaptive system known as ROMANCE. I went to Southhampton's ROMANCE website and found a cool link that gives you travel times on some main corridors through the city. Does the city use the data collected from the intersections to create this map and estimate the travel times along the signalized corridor?
http://www.southampton.romanse.org.uk/ (http://www.southampton.romanse.org.uk/)
(you have to click on 'Journey Times' tab in the legend)
Quote from: english si on August 22, 2011, 01:27:00 PM
I think it's ANPR (auto number plate recognition) and Traffic Cameras, though I'd imagine that they probably used to do with clever calculations with traffic lights and guesses at traffic speeds, but ANPR would be easier and more reliable.
I would hazard a guess that there is some sort of sensors out on the roads that do the calculation for a given segment. It's a bit tricky to get a travel time to be fairly reliable on a surface road, especially when there's signals and many intersections or driveways present.
As I said, ANPR would be more reliable than the complex calculations that other methods (radar sensors, induction loops, etc) would be for average speed. ANPR is also what they also use on the freeways in Great Britain for sites like Traffic England. Having some closed circuit visible light cameras and software that picks up number plates and then calculates the point-to-point time for number plates that appear on two cameras (and then ditches the number plate data, hopefully) would be the easiest and most accurate way, now the software exists to process the video (though it was invented in the 70s), to measure average speeds - especially if there are driveways and side turns and stuff.
Doing a bit of digging (though it hardly took any), ROMANSE does use ANPR for journey times. Traffic signals will use the induction loops (given they are all at junctions, it's not good for journey times as the speed data would be off) as they use SCOOT (http://www.scoot-utc.com/).
Around Chicagoland, two methods are used. IDOT tends to use induction loops buried in the expressways, and has started using a system more like ANPR. The Tollway uses I-Pass data. They track I-Passes along a given section of tollway to determine speed and congestion.
Quote from: Duke87 on August 15, 2011, 09:41:01 PM
Quote from: tradephoric on August 15, 2011, 11:20:39 AM
Well, the one way avenues are nicely timed to have the lights progress up the block at about 30 MPH (the speed limit). And indeed, if traffic permits, you can expect to drive 20, 30, even 40 blocks up 1st Ave without hitting a red light.
Park Avenue and other two-way avenues, naturally, do not and cannot have such convenient light timing. There you will hit a red light every 5-10 blocks because, while the greens do at least seem to cluster together, they can't be made to progress with traffic since traffic goes both ways. I don't know what the precise strategy is. But I do know that NYC traffic signals are controlled by boxes at the site of the signal itself (some of which are mechanical - you can hear parts click and clank in there as the light changes!). They don't have a central computer controlling things. So, whatever coordination there is between signals is all still done the old-fashioned way: by having guys go out and set the up one by one onsite.
"Click and clank as the light changes"? Man, what is this, the 1940s? :D
NYC also has signals that are at one way streets without any cross traffic that warrants its need. For example: Central Park West has stoplights on inward one way streets away from Central Park on the east side of this road and they are timed to turn red with the others (one way outward onto this street with lights) spite there is no reason to stop anybody for anything. If a pedestrian wants to cross the street at anytime a simple crosswalk button can be installed.
Quote from: roadman65 on February 29, 2012, 06:59:48 PM
NYC also has signals that are at one way streets without any cross traffic that warrants its need. For example: Central Park West has stoplights on inward one way streets away from Central Park on the east side of this road and they are timed to turn red with the others (one way outward onto this street with lights) spite there is no reason to stop anybody for anything. If a pedestrian wants to cross the street at anytime a simple crosswalk button can be installed.
You don't understand NYC. Pedestrians are ubiquitous. The traffic lights are absolutely about them, and given the volumes present 24/7, NYC is fine with a fixed-timing system that allows crossings at every block.
Quote from: Master son on August 16, 2011, 01:36:56 PM
ANY central business district is going to have traffic lights at nearly every block. I know Chicago and Milwaukee do for sure. I bet most of NYC - especially Manhattan (midtown and lower in particular) have such.
Since this thread is back at the top, I'll post the following...
You mention that most CBD's will have lights at every block, but what about places where signals are even more frequent than that? Downtown Seattle has several signalized mid-block crosswalks. Heading south on 5th Avenue from Pine Street to University, not only will you hit a signal at each of the four intersections, but also at three pedestrian crossings.
This doesn't meet the criteria of the original post though, as it's a one-way street, and generally well-timed.
Kirkman Road in Orlando, FL has way too many signals on it. The spacing between them is 1/10 of a mile through the Metro West/ Valencia College area. During rush hour, get prepared to be stopped at every one of the signals (or 90 percent of them anyway) from FL 50 to FL 482. Long waits at LB McLeod and Vineland as well as the Major Boulevard entrance to Universal because these are other arterials with 4 movements (3 at LB McLeod cause its a three way intersection) and a long crosswalk at the theme park.
W Burnside in downtown Portland...not only are there lights at every cross-street, there are no left turns. Most of the cross-streets are one-way couplets, so if you're driving westbound on Burnside and want to turn left to go south, you need to turn right (on a northbound one-way), then right, then right again.
Also, E 13th & 14th Aves in Denver are a one-way couplet that have some "pedestrian" lights mid-block, and they seem to turn red at random, methinks to keep one from exceeding the speed limit. There never seem to be pedestrians when these lights turn red. These aren't the only streets that have these either, but these are ones that seem to annoy me the most.