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Study: Traffic lights should respond to cars, not the other way around
- shotgun 16y agoIf I had a nickel for every time I was at a stoplight and thought the same thing...
- swah 16y agoWell, then just remove the lights and go back to cars responding to cars.
- Tyr42 16y agoI do remember there being an article on here about just that. It seems to have some success. Also: Roundabouts. Edit: I guess I should read the two links that I open in background tabs _before_ posting. Now I feel like a fool.
- alecco 16y agoGetting rid of cars as much as possible in congested areas is the best way. Promoting very good public transportation and prioritizing people walking and riding bicycles. If they optimize the flow of cars in a little time there will be more people using cars in those areas and no operations researcher can solve that bigger traffic jam. People, like any biological entity, adapt to the environment.
- sigstoat 16y agobuses, trucks, emergency vehicles, bicycles on the roads, taxis, people going places too out of the way for public transportation to service and whatever other uses of the roads that aren't immediately obvious would all still benefit from this. smoother traffic flow and reduced time on the roads would also reduce accidents, which would require fewer vehicles be manufactured, which is a nontrivial environmental impact in and of itself. oh and fewer humans would die in horrific accidents.
- sgibat 16y agoplus it will be easier to integrate the infrastructure when cars go automatic
- jdc 16y agoI don't see how it's self-evident public transportation and bikes work best for all environments.
- eru 16y agoIt's more about the externalities. Your car is fine for you, but it has strange effects on other people. I agree though, that it's a testable proposition, and not self-evident.
- justlearning 16y agoeven better: here was someone who tried to change it for good: http://en.wikipedia.org/wiki/Hans_Monderman http://en.wikipedia.org/wiki/Hans_Monderman http://www.wired.com/wired/archive/12.12/traffic.html http://www.wired.com/wired/archive/12.12/traffic.html there is also a brief interview on youtube with him explaining his theory of change.
- metellus 16y agoThe only reason his intersections are safer is that the lack of signage makes drivers uncomfortable and therefore more careful. Get rid of signs everywhere and that discomfort goes away.
- sliverstorm 16y agoIf they remove timers from lights entirely, they better improve the sensors. There are already numerous lights that do not detect the presence of my motorcycle.
- bokchoi 16y agoWhen I'm riding my bike and I need to turn left, I'll jump up and down on the sensor. I look like an idiot, but usually it works! ;)
- marcinw 16y agoWhy not just buy a neodymium magnet? This usually does the trick to trigger the sensor.
- pak 16y agoThen one day, you kneel down to check your engine oil, and bam, there go all your credit cards. There are downsides. I'd prefer if they just made the loops a little more sensitive. A 200 lb piece of metal would seem to suffice for a true positive...
- kijinbear 16y agoSeriously, anything except a pedestrian should trigger the sensors. Car, motorcycle, bicycle, wheelchair, or a freight train from your subconscious trying to crush everything in its path... whatever it is, if it's sitting in front of an intersection and it's not on the sidewalk, chances are it's waiting for the green light! Sure, you might get a false positive from time to time, but whatever causes the false positive probably shouldn't be in the car lane in the first place.
- njharman 16y agoWith sensitivities that low false positives are triggered by cars in other lanes. Induction loops are very sensitive to variations. Believe me, I spent many hours on tweaking detectors.
- nollidge 16y agoSurely they mean "Traffic lights should respond to cars, AND the other way around?" The lights aren't really necessary if nobody's responding to them.
- krschultz 16y agoNot to sound like a radical libertarian but imagine a world in which roads were operated with some sense of incentives to actually MOVE TRAFFIC THROUGH. Lets have Tolls - but you get a refund when you are delayed. I imagine construction would suddenly be done 24/7 and be finished in half the time. Traffic light systems would be heavily automated/AI so that there isn't much traffic. Instead they give out construction contracts to the "cheapest", which ignores all of the wasted time and gas the public endures in traffic, a secondary cost of the project.
- Anechoic 16y agoI imagine construction would suddenly be done 24/7 and be finished in half the time. You would be trading one set of inconveniences for another - in the case of nighttime construction you're typically paying the construction workers more (anywhere from time-and-a-half to triple time IME) plus the environmental mitigation for the nighttime activities (noise in particular).
- krschultz 16y agoAround here (NYC metro area) more of the construction is done at night than not at night. It is generally less noticable because if you aren't driving at 1 or 2 in the morning you don't see it, but I do a 100 mile drive about once a week at night and it is noticably different than the daytime. The biggest loss is not working weekends. And why do you have to pay so much? Construction workers have one of the highest unemployment rates, I bet if you start offering 3 shifts at day you would have people sign up for time or time and a half max.
- Anechoic 16y agoAround here (NYC metro area) more of the construction is done at night than not at night IME (having worked on several NYC-area construction noise assessments) that's not true, and when it is true, it's usually because the traffic disruption would be so severe, the project has no other choice. MTA/NYCT work also tends to occur at night because that's when train schedules are reduced and workers can have room/time to work. And why do you have to pay so much? Because working such a physically demanding job at night for extended-periods, especially in cold/wet weather sucks (again, speaking from experience). Looking at the Big Dig night work, younger guys were likely to sign up for night work to make a quick buck while the older, more experienced guys (usually with families) would use their seniority to get on day shifts so they could lead normal lives. This causes problems because you want the more experienced guys working nights so they get things right the first and don't have to wake up project engineers when they encounter problems, so you wind up upping the hourly wages to try to attract those experienced workers.
- points 16y agoRadical, but there's only one word needed here. ROUNDABOUT. Build some.
- ghjklkjh 16y agoBut four-way stops give the Americans so many opportunities to demonstrate their well known diffidence and thinking of other drivers.
- khafra 16y agos/diffidence/deference
- kes 16y agoI live in a small midwestern town that has recently taken to the idea of roundabouts. At first, I was extremely pleased (having good experiences with them in Paris/French HW systems) but I quickly became discouraged when I realized that 90% of drivers had no idea what they were doing. I now avoid certain routes through town because I'm afraid of getting in an accident.
- eru 16y agoWhat's so hard to get for those people? Roundabouts seem simple enough to me (though I may be biased, coming from Europe and now living in Britain).
- 16y ago
- AndyKelley 16y agoToo bad our government is too big and slow to actually do it.
- evo_9 16y agoI think it's more a matter of the money the government makes off of tickets and such. That's the biggest obstacle - the revenue that is impacted by this change.
- runT1ME 16y agoThe city I live in doesn't have any of it's lights on timers...Every intersection I've come to has sensors...
- sprout 16y agoShouldn't lights be optimized first to reduce accidents? I've always understood inefficiency to be an intentional safety feature.
- Empedocles99 16y agoKeep all lights red. Nobody moves, pretty simple heuristic solves for reducing automobile accidents.
- sprout 16y agoMaybe the ideal is that there are signals that permit bicycles and pedestrians, but if cars want to go they have to get out and push a button to get the light to let them through.
- ulvund 16y agoHere in Denmark a lot of traffic lights respond to road sensors. Another cool thing is the countdown in seconds for the pedestrian lights.
- csl 16y agoThose metal detectors 6 feet from the light post? This system seems to ensure that entire columns of cars can flow nicely through several intersections.
- jacquesm 16y agoIn plenty of countries this is a reality already. Sensors are placed anywhere from a few meters to hundreds of meters ahead of the actual lights to determine the flow of traffic, there are 'green waves' which you can synchronize with to guarantee uninterrupted passage (both for congestion control and to save fuel) and there are adjustments made based on the expected flow from different routes depending on the time of day. The future, in this sense at least, has already arrived. Sure there are plenty of places where this is not common yet, but infrastructure upgrades are expensive.
- WalterBright 16y agoThe wire sensor buried in the pavement has been around since the 1960's, and nothing has improved since then. You don't need to place sensors anymore, a simple camera can do it.
- jacquesm 16y agoIt's a bit more involved than that, nowadays there are many sensors instead of just one to detect a waiting car in front of the light, the speed gets measured as well as the number of vehicles. As for a 'simple' camera, nothing that you deploy in all weather conditions is ever simple if it is to operate reliably.
- WalterBright 16y agoOr even a directional microphone, or an infrared sensor, or a microwave radar, etc.
- jcnnghm 16y agoThey do this here, too. Last year the system failed spectacularly in Montgomery County (http://www.washingtonpost.com/wp-dyn/content/article/2009/11/04/AR2009110402413.html http://www.washingtonpost.com/wp-dyn/content/article/2009/11...), and it was a nightmare.
- tibbon 16y agoAs a motorcyclist, I'm going to disagree completely if the standard technology that is used to detect cars is used. Generally there's some sensor in the road that detects a large metal object above. If you're riding a 400 pound motorcycle, it doesn't trigger. I've sat at lights for several cycles trying to get a left turn signal, only to be required to run the light (illegally) to get through while traffic built up behind me. Not cool. They need a better way of sensing cars.
- deleted 16y ago[deleted]
- SeanLuke 16y agoA sort of vague way to do the green wave, but okay I guess. But -- and I say this in all seriousness -- one of my PhD graduate students had a far more interesting and elegant technique five years ago. In short: each car has a piggy bank. As you're sitting at a red traffic light, it dispenses tokens into your piggy bank. When you go through a green traffic light you have to give some tokens back. Here's the catch: when deciding who to give the green to, a traffic light awards the green light to the compatible set of lanes which have cars with the most total tokens. [Also: tokens expire. And emergency vehicles can be given infinite tokens]. Thus if you've been waiting at a zillion reds, you'll accumulate enough tokens to force your way through green lights later on. The idea is to spread the pain. http://cs.gmu.edu/~sean/papers/aamas06-traffic.pdf http://cs.gmu.edu/~sean/papers/aamas06-traffic.pdf
- brc 16y agoIt's a good idea but would really require the car to have interaction with the system, or the system to read and interpret individual cars (to assign the token). I think the advantage with the system shown is they are only measuring throughput rather than keeping tabs on individual cars. Thus I assume it's an easier problem to solve.
- khafra 16y agoYeah, for a lesser investment than that, they could put some basic sensors on so I'm not waiting with 10 other cars while a green light stays on 30 seconds in the other direction for absolutely nobody. "Improving traffic lights" is pretty low-hanging fruit.
- SeanLuke 16y agoThat's already been done.
- SeanLuke 16y agoWell yes and no. Our proposal wasn't to keep tabs on cars. There's no tracking whatsoever. Lights have no idea of knowing where you have been or who you are: you're just telling them how much pain you've been suffering in the near past. The tokens aren't marked -- they're simply currency so to speak. The approach does require two-way communication between cars and nearby traffic lights. But the approaches that various people are suggesting, including this article, largely rely on communication as well: just one-way. The lights generally need to be able to detect cars approaching and at quite a distance. This requires the cars announcing their presence: either the lights have a sophisticated sensor system (lots of plates in the road, or a vision system) or -- more likely -- the cars need to have beacons installed which let the lights know they're coming. A great many of these methods also benefit from knowing not only that cars are approaching but where they intend to go -- are they going to turn left or right or straight -- well before they get into their lanes. This requires additional signaling. What Gabriel Balan picked up on, is that to make the system fairer and more efficient, you need to be able to transfer historical information from light to light. Not only information about how many cars are coming, but what their previous histories were. If you don't want the lights communicating with one another -- essentially tracking your car -- you can do what he did: have the cars build up a history on their own and relay that to the lights as they approach them.
- blaines 16y agoWhere I live there are roads to nowhere and traffic lights in quiet neighborhood intersections. I'm not sure who 'engineered' the streets, but one car can stop a swarm of traffic, and the speed limits are many times ridiculously low i.e. 35mph on a two lane street in a non-residential area, high visibility, and no intersections within 2mi. This is a broken system in which much of my time is wasted daily, and the "green wave" is not the system's goal. It's nice to see some people experimenting to find better ways to regulate traffic. It should be obvious that 90% of the time the current flow is not the calculated daily average. After all, Since when do 50,000 cars/hour drive on a street at 2am?
- JulianMorrison 16y agoAlso for pedestrian crossings, tear up the button controlled lights and put in a zebra crossing. Those are so much faster. No need for the pedestrian to wait (nor scramble across in a panicked hurry, if they are old or disabled), no timer keeping the cars waiting after the pedestrian already crossed, and no pressed buttons which operate the lights after the pedestrian has gone
- ErrantX 16y ago"Traffic lights should respond to cars, not the other way around" True, but believe it or not it is incredibly difficult to get right. I'm on my local council and we recently did some prep work to look into adding "AI" to the towns traffic lights. Here is the problem; you have to do a significant portion of the lights - or it actually gets worse. A stupid amount of planning goes into light sequencing (at least it does here....) on a macro-scale - so all of the towns lights are pretty much synced to optimize traffic flow as much as possible. Imagine doing that on the fly for the entire town. What ''has'' been suggested, and looks good, is a sort of hybrid approach - where traffic levels are monitored and a number of different optimized sequences used to clear traffic jams as appropriate. Even this is a pain because it is essentially the same as replacing the towns system three or four times over :) And we are lucky in having a medium sized town with large areas of uninhabited farmland (read little traffic) around it. Not that it isn't a good idea - but I don't think it is a very simple option.
- cliveholloway 16y agoAnd let's not get into "intelligent pressure pads". The number of times I've had to run a red light at night because the pad doesn't register my bicycle...
- buss 16y agoHere in downtown Seattle the traffic lights are timed for pedestrians. One can walk from one end of the city to the other without waiting for a light to change.