|
thehustler posted:Everytime a thread like this comes up I always post this link: Those where the first websites that showed me that I wasn't the only strange road geek in the UK. I recommend going to these websites as they do give interesting information about roads that isn't constant 
|
#
?
Jul 29, 2009 20:14
|
|
"
|
|
| # ? Apr 25, 2024 13:37 |
|
|
Awesome thread! What do you think about radar signs?  They seem far more imposing than normal speed limit signs.
|
|
#
?
Jul 29, 2009 20:23
|
|
|
Vanomaly posted:Awesome thread! I just saw an interesting variation on these near Chicago. Rather than show your speed, it was a regular speed limit sign with an LED/strobe light border that would start flashing at you if you were going well over the limit. I think this is a better idea.
|
|
#
?
Jul 29, 2009 20:33
|
|
|
problematique posted:if you jumped on 28 you'd get to Orbital pretty quick, even quicker now with them getting rid of the lights in that area. That's what I've been doing since they removed the lights between Route 7 and Steeplchase. Also, they're closing left turns from Route 28 to Steeplechase starting August 3rd. They will still allow right turns from Steeplechase to Route 28 though. I feel your pain about driving on Route 7 in the mornings, I shouldn't complain! Merrack posted:This has been so weird to see, watching 28 become a highway (complete with a speed limit raise!) It's about time! What's the new speed limit on 28? I still see signs for 55mph. voltron fucked around with this message at 21:46 on Jul 29, 2009 |
|
#
?
Jul 29, 2009 21:41
|
|
|
Mank posted:I just wondered about dynamic message signs, or, as you may call them in Connecticut, variable message signs or changeable message signs! I can't remember which you guys call them; it seems to vary from state to state. I still use the Rhode Island nomenclature, which is to call the roadside signs VMS, the overhead ones DMS, and CMS as a catchall. quote:You mentioned that you had some sort of experience with them, so I wanted to ask what types of attributes you looked for in them. What features are important to you? What types of problems have you had with them that make technicians heads explode? We used a few brands, but my favorite was Daktronics. Their software was excellent, and made designing new messages a breeze. Some people complained that they only had 2 colors (or three, depending on how you look at it), but electronic signs really shouldn't show flashy messages. We hardly ever used anything but amber, as green's tough to see at a distance and red is only for emergencies. quote:Also, have you helped with writing any specs or anything for DMS contracts? If so, what goes into that process? I assume it's usually low bid, but are there manufacturers that you prefer over others? We specify a couple brands "or approved equal," which is pretty standard. We try to cut down on proprietary specs. Really, though, VMS issues are usually the least of my concern. If they don't work, we call in someone to fix them. It never ends up being my problem.
|
|
#
?
Jul 29, 2009 21:58
|
|
|
Binge posted:They're putting roundabouts in right next to where I live on the highway here. The highway begins here at Lake Ontario (I-590) and and goes to meet up with the other interstate branches and eventually I-90. The first 2 or 3 miles of it, has always been 4 stoplights. The one I use to enter the highway gets way too many accidents a year. People going 55, tend to try and beat the lights as often as possible. They stay yellow for a long time, which I think gives people the confidence to just go for it. Unfortunately, many miscalculate the time and distance needed and careen into cars making left's or right's onto the highway. That's great! I'd be a little concerned about the roundabouts handling the amount of traffic that goes there, but they'll definitely slow down traffic and make the roads safer, and that's always the #1 goal.
|
|
#
?
Jul 29, 2009 22:00
|
|
|
Powered Descent posted:Very interesting thread; thanks, OP! A new transportation policy called ISTEA-LU (the acronym is just a bunch of buzzwords) a few years back requires us to consider all modes of transportation, not just cars. In general, I visit my projects and look for signs of bikes. If I don't see any signs, and it's not on a marked bike route, I don't worry too much about it. Some projects are all about the bikes! Half an hour ago, I got a new project: a multi-use trail alongside a river. That's going to be fun to design. Connecticut has statewide numbered bike routes. We're working on changing them from "wide shoulders = bike path" to "old rail trail = bike path," since some of the routes are pretty lousy for bikers. I'm sure you'd rather ride on a separate road, instead of having to share the road with cars. I know there's a lot of animosity between cars and bikes, and it goes both ways, so why not keep them apart? Old railroads provide some great access between towns, as much as it hurts me to pave over rail.
|
|
#
?
Jul 29, 2009 22:06
|
|
|
Thomamelas posted:It's been a number of years since I lived in CT, but I think that's west of Meriden by I-84. Bingo, CT 10 and CT 322 (former Rte 66) in Southington. I-691 is a half mile to the south.
|
|
#
?
Jul 29, 2009 22:07
|
|
|
Arafa posted:
He gave a couple answers but I have another. In defensive driving you're taught to leave a car length in front of you until someone pulls up behind you. This way if you get rear ended you wont smash into the car in front of you. This isn't exactly what you're talking about because you're supposed to move up pretty quick and I don't really follow it myself but it's just an idea.
|
|
#
?
Jul 29, 2009 22:24
|
|
|
crumpuppet posted:There's an intersection in my city that has an all-red phase which lasts 5 seconds, instead of the standard 3 seconds found everywhere else. This can be confusing if you don't know about it. I often see people expecting the standard 3 seconds, causing the whole line of cars in the front to lurch forward only to have to wait another 2 seconds for the lights to go green. This is a perfect opportunity to explain how we calculate what we call red clearance intervals, or all-red time.  First, as shown in blue, you sketch out all the paths cars take to leave an approach. Then, you draw the side road paths that could hit them (red). I've left some out here for simplicity. For each conflict point (shown in yellow), you do the calculation shown in the lower right. The 22 fps is an assumed 15 mph speed for someone entering an intersection on a fresh green. We add one second because people love to run red lights, and safety first! Having a red clearance over 5 seconds is unusual, but can easily occur if the main road is very wide, or the side street has a low speed limit.
|
|
#
?
Jul 29, 2009 22:25
|
|
|
Phone posted:Can I print this off as a "get out of jail free" card when an officer eventually pulls me over for making a left on red? You say that now, but wait until some old man who doesn't see your car pulls out in front of you and totals your car  I suppose that could happen at any intersection where permissive lefts are allowed, though. Another concern I didn't mention is that on multi-lane approaches, a truck waiting to turn left could block your view of oncoming traffic.And if it seems like I'm picking on the elderly, it's because they generally define our standards. They have lovely eyesight (you need twice as much light to see at night for every decade past 25 years old), lovely hearing, lovely reflexes, and have a tendency to drive the wrong way on freeways and pass out behind the wheel.
|
|
#
?
Jul 29, 2009 22:31
|
|
|
DaisyDanger posted:Why do certain places have those god awful traffic lights that are impossible to tell which color they are until you're right under them? I get it, "ha ha! Those pesky drivers will have to slow down to see if they're ok to pass through the intersection!" but really, I imagine it would just create more traffic. My coworkers and I all hate those. They're called optically-programmed heads, which is engineerspeak for "you can only see them from a very small area." We mainly use them here when there are two approaches at a very acute angle, and it's extremely important that they don't see each others' signals. Luckily, we only put them on the green indications. Yes, it does slow people down, and some jurisdictions could put them up expressly to slow people down. I wouldn't do it, myself.  I also hate them because they tend to get knocked around and point in the wrong direction! At that very intersection, I once encountered some huge backups because the heads got blown around and the green balls were only visible from... well, I don't know, but not where they were needed. There were huge queues, as people couldn't tell when they could go. I called up maintenance and told them the lenses were misaligned. They told me, "Yeah, they're supposed to be that way. They're special!" I wish people could see me flipping them the bird over the phone.
|
|
#
?
Jul 29, 2009 22:36
|
|
|
thehustler posted:Everytime a thread like this comes up I always post this link: Thanks for the links, I remember you posting these last time I went roadspergin' in a GBS thread. I posted it before, but https://www.kurumi.com has some interesting stuff, including a complete list of every three-digit interstate in the US.
|
|
#
?
Jul 29, 2009 22:39
|
|
|
MarshallX posted:Apparantly VISSIM has a trial that last 2 monthes - I'm downloading it right now to give it a shot. VISSIM has a TERRIBLE interface. You can only layout roads in 2D mode (right-click and drag while you have link mode selected), you place 3D objects in 3D mode only, except for signals, which are the only object in the entire program that can be copied or pasted. Yep, you read that right. The drivers are incredibly retarded most of the time, and setting up a four-way stop takes ages, since you have to define every single conflict area. On top of all that, there is no undo button. Now my German teachers have told me that Germand NEVER make mistakes, and this program seems to confirm that. All the same, it's a ton of fun to use once you get the hang of it. You can make such funny or cool looking things, like making a cannon that shoots cars through the sky (on an invisible road). Other software? Engineering software isn't made to be fun, but I'd recommend Synchro. It's very easy to do signals in there, and there are few things more fun than making an 8-approach intersection with a dozen lanes each and watching the chaos.
|
|
#
?
Jul 29, 2009 22:44
|
|
|
Mr. Chupon posted:Fantastic thread, if I had decided to do any other discipline of engineering I think it would have been traffic. I'll show you coordination 102 once I teach you guys about how signals are laid out and their naming conventions. 102 should answer some of your questions. Every coordinated signal group is based around a Master controller. The Master sends time synch signals to all of the slave controllers, each one of which has an offset. For intersecting major roads, it would be pretty easy to put the Master at the intersection, and just set the phasing and offsets to optimize flow.
|
|
#
?
Jul 29, 2009 22:48
|
|
|
psydude posted:OP - anybody who has ever driven by, in, or around DC has had to deal with this monstrosity. On top of being incredibly confusing (I've driven through it numerous times on the way to and from school, and I still get off on the wrong exit), it also seems like the amount of congestion resulting from it is constantly a problem. Can you see any logic behind what the engineers building this interchange were thinking? Well, the fact that it's being rebuilt should tell you something about how well it was designed Correct me if I'm wrong, but I'd say the problem with that interchange was that I-95 was supposed to go through DC, not around it. Dumping all the I-95 through traffic onto the beltway, which was probably designed for much lower volumes, pretty much killed the LOS. Do you have any pictures of the interchange before it was redesigned? I'd be glad to pick it apart.
|
|
#
?
Jul 29, 2009 22:51
|
|
|
So I have a hypothetical question for you: In Chesterfield, Rt 85 meets with Flanders Road. At that intersection there is a lake on the side of Rt 85. If you're coming from New London, you will be heading downhill with the lake on your left. When I was living there it wasn't uncommon to drunk drivers to end up in said lake. Short of draining the lake, how would you fix that?
|
|
#
?
Jul 29, 2009 22:52
|
|
|
Vanomaly posted:Awesome thread! Undeclared Eggplant posted:I just saw an interesting variation on these near Chicago. Rather than show your speed, it was a regular speed limit sign with an LED/strobe light border that would start flashing at you if you were going well over the limit. I think this is a better idea. At first, those were great for lowering speeds. Then, when people figured out they wouldn't get tickets, they became "See how fast you can go!" invitations. We decided to fight back: our specs say that, if someone is driving more than a few mph over the limit, the sign won't show their speed. The radar signs do lower speeds for as long as they're used, but as soon as they're removed, people go right back to speeding. It's very useful around temporary safety hazards, such as work zones. As to strobes, I think the draft MUTCD specifically says not to use them, since they can trigger epileptic seizures. All it takes is one Blinky Von Crashalot passing out and smashing into a work zone, and strobes get phased out.
|
|
#
?
Jul 29, 2009 22:57
|
|
|
voltron posted:That's what I've been doing since they removed the lights between Route 7 and Steeplchase. Also, they're closing left turns from Route 28 to Steeplechase starting August 3rd. They will still allow right turns from Steeplechase to Route 28 though. I feel your pain about driving on Route 7 in the mornings, I shouldn't complain! It's really nice to see arterials turned into freeways. It gives me some hope about the future of New England's freeways. Unfortunately, it's only recently that we figured out to restrict driveway access to big roads, so we'd end up cutting off access to businesses. Congrats to your DOT for having the foresight to pull that off.
|
|
#
?
Jul 29, 2009 22:59
|
|
|
Thomamelas posted:So I have a hypothetical question for you: I'd put up guard rail in the area. Depending on how much land was available at the edge of the road, one of these three would do:  If that didn't work, I'd shift the road alignment away from the lake. Edit: Or finish Route 11
Cichlidae fucked around with this message at 23:19 on Jul 29, 2009 |
|
#
?
Jul 29, 2009 23:16
|
|
|
Another lull in the questions, and that means we get a lesson on SIGNAL NOMENCLATURE! This is a big one, so if you don't understand something, please let me know and I'll explain it another way. As our visual aid, I've taken a nice big intersection. Big intersections are best suited for a signal style known as a dual-ring quad. Check it out.  First, we align the drawing so that the most important street is going up and down. Then, going clockwise from the top, we number the four through (straight) movements: 2, 4, 6, 8. Next, we number the left-turn movements 1, 3, 5, and 7. The movement 1 conflicts head-on with 2, 3 conflicts with 4, 5 conflicts with 6, and 7 conflicts with 8. Still with me? The point of this numbering is the little diagram on the lower left. This phase diagram consists of two "rings," meaning that two movements can go at once, and a "barrier," which splits the movements nicely into main street and side street. So the secret is, each ring has one of its movements going at any given time. Additionally, any movement from the top can go along with any movement from the bottom at the same time, as long as they're on the same side of the barrier. 1 can go with 5 or 6, as can 2, but 1 cannot go with 2 since they're on the same ring. The diagram on the lower right shows each of the 8 resulting combinations, split by the barrier. When the controller enters a barrier, depending on where vehicles are present, it can start on any one of its four phases. In this case, we have what's called a lead left signal, which means that left turns go before through cars. So, if there's a southbound car wanting to turn left, the controller will offer movement 5 some green time at the beginning of the barrier. If there are no southbound cars, then movement 5 is useless. Using the little diagram on the lower left, we see that movement 6 will be called instead. 6 can go along with 1, if there's anyone turning left northbound, or 6 can go with 2 instead, with cars moving straight through the intersection on the main road. The controller will rest on this phase until a call is received on a side street, at which time both rings will cross over the barrier together, and we drop to the second half of the diagram. I know it's a lot to absorb, so let me know if you need more help. I've got a lot more to teach!
|
|
#
?
Jul 30, 2009 00:35
|
|
|
Rt. 6 in CT Begin you rant.
|
|
#
?
Jul 30, 2009 00:48
|
|
|
Crackpipe posted:Rt. 6 in CT Well, let me begin with some history. US 6 is a federal road crossing Connecticut (and the rest of the US) in an east-west direction. Before it was US 6, it was New England Interstate 3. That's right, New England had its own interstate system in the 1920s, but they were very different from what we now consider an interstate. They were narrow, 2-lane roads, snaking through countrysides and hitting every city on the way. Many of these important roads were made federal routes, such as US 1, 5, 6, and 7 in Connecticut. When they began to get congested in the 1940s, the government planned a series of freeways to relieve congestion. Some of these run alongside the route they're meant to replace (I-95 and US 1, for example), some took new routes to cut travel times or bypass cities (most 3-digit interstates beginning with an even number, like I-295 around Providence or I-495 around Boston). US 6, which carried most of the traffic between Hartford and Providence at the time, sorely needed a bypass. The feds planned a new interstate, I-84, to fulfill this goal. I-84 was to take roughly this route:  Rhode Island and Connecticut both got interstate miles for it, and began construction immediately. Connecticut had already built a 5-mile stretch from what would later become I-395 to the Rhode Island border, and 84 could overlap with the former CT 15 expressway, by then named I-86, east of Hartford for a few miles.  After some time, Rhode Island got smacked down by the EPA for dicking around with their environmental impact statement. It turns out, there would be too much impact to the Scituate Reservoir (that V-shaped lake in the pictures), and RI couldn't build its half of the freeway. Well, Connecticut wasn't happy with that, because US 6 was already known as "Suicide 6" in the area, especially where it went through downtown Willimantic, a city which had earned a reputation as the heroin capitol of the East Coast. We're talking winding, narrow roads, sandwiched between buildings, driveways all over, and handling tens of thousands of cars a day for 80 miles. Connecticut's governor at the time had a lot of sway with the feds, and he got them to build the 5-mile Willimantic Bypass. It's worth noting that, at this time (and for the next decade and a half), the few miles of I-84 east of Hartford and I-86 weren't connected at all. In order to get between them, it was necessary to exit the highway and take local roads.  A few years later, Connecticut officially gave up on I-84. The signs on the Willimantic Bypass were changed to say US 6, the old US 6 in Willimantic was added to CT 66 (another failed interstate bypass candidate), and "Suicide 6" looked to be permanent. Connecticut begged the feds to at least finish the expressway to the Rhode Island border, even if RI couldn't build its part. Unfortunately, because of some political dick-waving between the two states related to I-95 20 years earlier, RI stuffed the deal and CT was left with four unconnected chunks of freeway. I-86, linking Hartford and Boston, was renamed to I-84, and the small stretch of I-84 in East Hartford and Manchester was changed to I-384. Around 1990, the state finally got around to connecting I-84 and I-384, eliminating the local road problem. We've also been doing continuous safety improvements on US 6 in the old "Suicide 6" corridor: widening the road, straightening it out, adding left turn lanes so people don't get rear-ended... you still get the feeling that it's not safe, but, in fact, not a single point between the end of I-384 and the Willimantic Bypass has abnormally high accident rates anymore. The stretch between the bypass and Rhode Island is still a mess, unfortunately, as is Rhode Island's non-freeway portion of 6.  That is the current state of the road. Green is freeway, red is non-access-controlled driving hell. Now, are you ready for some irony? Rhode Island recently got its poo poo together, and decided it would be possible to build the freeway past the reservoir. With a lot of luck, and some federal money, it could happen within the next 20 years. Connecticut, on the other hand, has been trying to connect I-384 to the Willimantic Bypass for 2 decades. There's a huge battle between the Army Corps of Engineers, the EPA, Connecticut DEP, and ConnDOT as to how it should be built. Hundreds of alternatives have been looked at, but there's never been a consensus. Several years ago, the state asked the Secretary of Transportation to step in and resolve the issue, but he hasn't, despite President Bush putting the project on his national priority list - along with CT 11, but that's a story for another day.
|
|
#
?
Jul 30, 2009 01:47
|
|
|
tell me about yellow light timing (and the people who shorten them for money)
|
|
#
?
Jul 30, 2009 03:15
|
|
|
What are your opinions on red light & speed cameras? Do you find that they help? Also my area has variable speed signs. If I remember correctly it took a drat long time for them to work(the first software they used ended up not working and then the company went bankrupt). I personally believe the variable speed signs were a waste of money, people will still go 65/70 even if the speed has been reduced to 45(usually indicating a jam ahead). Also what is your opinion on adding toll lanes on the interstate system, eg http://www.95express.com/
|
|
#
?
Jul 30, 2009 03:32
|
|
|
nm posted:tell me about yellow light timing There are two schools of thought when it comes to yellow times. The first, used in the UK, is that all yellows should be three seconds long. That goes right along with what we call driver expectancy. People drive more safely when they know how long the yellow is going to be, and don't have to guess whether or not they can beat it. They'll tend to run the red more often, but you can just make the red clearance longer to compensate. Funny aside, it's technically illegal to run a yellow light in some places. I highly doubt it's enforced, though. The second school of thought, and the one we espouse, dictates that the yellow time is proportional to the approach speed. People driving faster will take longer to stop, and will travel a longer distance before they can react. The grade of the road also matters, because one can stop faster going uphill. We assume that cars will decelerate at 10 feet/second squared maximum, or about 3 m/s^2. That's just fast enough to be uncomfortable. Reaction time is assumed to be 2.5 seconds, but it can be up to 4 seconds for old folks. Imagine that: the light turns yellow, then red, before our good friend Granny McOld even notices. She then screeches to a halt, crushing dozens of girl scouts who chose that fateful moment to cross the road, scattering cookies across the asphalt like so many broken dentures...
|
|
#
?
Jul 30, 2009 03:43
|
|
|
Cichlidae posted:Funny aside, it's technically illegal to run a yellow light in some places. I highly doubt it's enforced, though.
|
|
#
?
Jul 30, 2009 03:47
|
|
|
Arafa posted:And here is my $10,000 question. When stopped, why do some drivers leave gigantic spaces between themselves and the next car, even in tight left turn lanes and other very congested spaces? This has to be one of the worst and most avoidable forms of congestion. Yet I can never find any consistent reason why people do it. I've asked a lot of people and no one really seems to know why. Because of that, I think it must be some unconscious force, like an excessive desire for control or safety or something. Any thoughts? Vanomaly posted:Awesome thread!
|
|
#
?
Jul 30, 2009 03:54
|
|
|
Unlucky Sven posted:What are your opinions on red light & speed cameras? Do you find that they help? I don't have much against red light cameras, as red light running tends to cause lots of accidents. That doesn't mean I'd want to install any in my projects, though. The DOT has a pretty negative reputation here already, and I don't want people showing up at my doorstep with torches, burning effigies of traffic tickets. Speed cameras actually bother me quite a bit, mostly due to my attitude about speeding. They're pervasive in Europe, and the subject of universal fury. Fortunately, sooner or later, you remember where they are, and then they're effectively useless. The only real solution is to have speed camera boxes all over the place (protip: most of the time, the boxes are empty. It's not cost-effective to have the cameras everywhere, all the time). Even as a revenue source, speed cameras show a quick spike, and then pretty much flatline. quote:Also my area has variable speed signs. If I remember correctly it took a drat long time for them to work(the first software they used ended up not working and then the company went bankrupt). I personally believe the variable speed signs were a waste of money, people will still go 65/70 even if the speed has been reduced to 45(usually indicating a jam ahead). I'd think a general-purpose VMS would be a better use of the money, then it could just say "CONGESTION AHEAD / DRIVE WITH CAUTION" or the like. A variable speed limit sign without context is just asking to be violated. (Disclaimer: do not violate speed limit signs, they are incapable of giving consent and it is very easy to recover your DNA from their slutty little posts. Take it from me!) quote:Also what is your opinion on adding toll lanes on the interstate system, eg http://www.95express.com/ Tolls are illegal in Connecticut since 1988, and only exist in one place in Rhode Island, but the Governor recently mentioned allowing single-person vehicles in the HOV lanes with a special (paid) permit to raise revenue. Putting up tolls severely curtails the amount of federal funding available for roadwork, so it might look good on paper, but it's not so great in practice. I'd much rather see the state bump up the gas tax by 10 or 15 cents (it's 14 cents lower now than it was in the 90s), as the net effect would be the same without adding another charge to my credit card every month.
|
|
#
?
Jul 30, 2009 03:56
|
|
|
nm posted:Its technically illegal to "run" a yellow in nearly every state if you can stop safely. I imagine that'd be hell to enforce, though. What one person considers safe deceleration might mean something else for another. Would it be worth it for a trooper to dock someone on a charge like that? Anyway, time for bed. Give me some questions to think about at work tomorrow!
|
|
#
?
Jul 30, 2009 04:00
|
|
|
what kind of interchange is this? I loving hate it. http://maps.google.com/maps?f=q&sou...4,0.013937&z=17
|
|
#
?
Jul 30, 2009 04:09
|
|
|
I am pretty certain that's a cloverleaf. He mentioned all sorts of kinds on page two I think.
|
|
#
?
Jul 30, 2009 04:37
|
|
|
DaisyDanger posted:I am pretty certain that's a cloverleaf. He mentioned all sorts of kinds on page two I think. Yeah I saw that post, it's just drat obnoxious. Traffic gets backed up like mad as the on ramp lanes get backed up by two different highways merging into a single line and then waiting in a queue to get onto 1604 It's a pretty new interchange too!
|
|
#
?
Jul 30, 2009 04:41
|
|
|
Great thread! I have always been miffed by the misalignment of traffic light timings and I'm glad that I'm not the only one thinking about it. And of course, questions: 1. There's a saying in Chicago that there are two seasons: winter and construction. It seems to me that highway construction takes unreasonably long to complete (ahem route 88). Is this a consequence of always hiring the lowest bidder? Are union workers being lazy? Or is road construction a lot harder than I think it is? 2. I'm not sure if this is just a Chicago thing, but we have annoying diagonal streets in areas with otherwise only north/south and east/west roads. These diagonal streets create many slow three-way intersections which greatly increase traffic. Chicago had a clean slate to design the roads however they'd like after a fire destroyed downtown in 1871 - why would they introduce these diagonal streets? 3. Could we get some idea of road costs? For example, how much does a mile of road cost? A mile of highway? Are bridges really expensive? How much does cost affect your designs? 4. If you could design all of a city's transportation (roads, highways, and public transport) from scratch, how would you do it? If it helps, let's pretend our hypothetical city is symmetrical and on flat land, with population density decreasing from the center.
|
|
#
?
Jul 30, 2009 05:43
|
|
|
Cichlidae posted:This was very interesting. I've seen two kinds of timings used in intersections like this. Usually, intersections like this will cycle 1-5, 2-6, 3-7, 4-8, skipping the arrows if there are sensors and nobody is turning left. However, occasionally, I'll come across one that cycles through each direction clockwise, 1-6, 4-7, 2-5, 3-8. It typically takes a lot longer to move through that cycle. What sort of conditions or factors go into deciding which of those cycles to use?
|
|
#
?
Jul 30, 2009 05:47
|
|
|
Cichlidae posted:I imagine that'd be hell to enforce, though. What one person considers safe deceleration might mean something else for another. Would it be worth it for a trooper to dock someone on a charge like that? Pretext for traffic stops though.
|
|
#
?
Jul 30, 2009 06:11
|
|
|
http://maps.google.com/maps?f=q&sou...006968&t=h&z=18 How do you deal with things like that? That intersection was pretty obviously designed for 4 roads and the fifth was probably hastily added by the town at the last minute. It screws up traffic flow pretty badly. Moving down that road a couple of miles: http://maps.google.com/maps?f=q&sou...006968&t=h&z=18 You can get off I-95 and immediately get on in the opposite direction without any effort. Is that a bug or a feature? Crackpipe posted:Rt. 6 in CT I see your move and raise you I-91 in New Haven. Or more specifically, "oh god oh god what am i going to do with this highway i'll just make it end in the center of the city" As far as I know, the plan was: - Exits 2 and 1 shoot off into downtown New Haven. - I-91 ends in the parking garage and entices people to pay exorbitant fees to stay inside. - A road comes out of the lower level of the garage and gracefully rises to meet Route 34. Several blocks of a neighborhood were razed to make room for this. The plan, as actually implemented: - Exits 2 and 1 shoot off into downtown New Haven. - I-91 ends at those exits. - Several blocks of a neighborhood were razed. - DONE!  I know it's probably more of a problem of urban planning than traffic engineering, but...how do you mess that up? 
|
|
#
?
Jul 30, 2009 06:17
|
|
|
Meet the most dangerious interchange in Sacramento http://maps.google.com/maps?client=...14&z=16&iwloc=A Biz 80, US 50, and 99 Can you tell me where and why? Also: Ring roads? Are they as awesome as I think? nm fucked around with this message at 06:41 on Jul 30, 2009 |
|
#
?
Jul 30, 2009 06:32
|
|
|
nm posted:Meet the most dangerious interchange in Sacramento I mentioned the hate for this interchange a little while back. I am 99% certain that when 5/50/99/80 were linked, they didn't decide to intentionally make it a nightmare. The fact that it is built OVER part of downtown definitely requires it to be squished into whatever possible configuration. Sacramento just has some horrific highways. The EB Cap City and 80 merge right by Madison is a good example.
|
|
#
?
Jul 30, 2009 07:06
|
|
|
|
| # ? Apr 25, 2024 13:37 |
|
|
Bum the Sad posted:what kind of interchange is this? I loving hate it. That's a cloverleaf with service roads and collector/distributor roads. Given the number of cars shown in that satellite photo, I'd imagine that it can't quite handle the volume it takes, and there's some weaving issues. The service roads only have one U-turn ramp provided. Sound about right? Edit: that was before reading your second post. Looks like that's pretty much the issue, along with interchanges not being spaced far enough apart. Remember, 1 mile is recommended! Cichlidae fucked around with this message at 12:22 on Jul 30, 2009 |
|
#
?
Jul 30, 2009 12:17
|
|