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Systemic traffic jams caused by small groups of drivers, study says
- tokenadult 14y agoThis is a very interesting report. It was based on anonymized tracking of cars with cell phone GPS signals to better understand the whole traffic network of the Bay Area. Identifying choke points for traffic led to a policy proposal. "John Goodwin, a spokesman for the Metropolitan Transportation Commission, the region's transportation planning agency, says the best way to spread out traffic coming from these neighborhoods is to install metering lights at their freeway onramps, which spaces out the traffic to help both those drivers and everyone else get to their destinations quicker. Though many important Bay Area freeways already have metering lights, such as Interstate 280 in the South Bay and Interstate 680 in the East Bay, others don't." The Twin Cities metropolitan area, where I live, was the first place in the United States to gain special federal permission to put on-ramp metered signal lights on federal Interstate Highways used heavily by commuters. They empirically help a lot in smoothing traffic. One reason we know that is that for a while a doofus state legislator shut down the freeway metered ramp program, until traffic here became so unbearable that the meters were put back in use. I have heard from friends who travel here from other parts of the country that the ramp meters (implemented as red-yellow-green traffic signals just before a car gets onto the freeway) are confusing to people who usually drive where on-ramps are just unimpeded paths onto the freeway. But they definitely speed up traffic. The Twin Cities has one federal highway, Interstate 394, with a pair of reversible lanes, usually eastbound (into Minneapolis from the suburbs where I live) in the morning, and westbound (out of the city into the suburbs) in the evenings. That helps with rush hour commuter traffic, except that a lot of cars are eastbound for evening appointments even as commuters are leaving the city, so the reversal of lanes still leaves the regular, nonreversible lanes badly congested each evening. I wonder if a traffic study like the one reported in the interesting article submitted here could identify how to smooth out the traffic problems we still have here.
- mrb 14y ago"It was based on anonymized tracking of cars" If it was anonymized, they could in theory release the data, right? However the article states "all the data gathered in the study will be kept confidential". Don't these 2 statements contradict each other? Why would they need to keep anonymous data confidential?
- anigbrowl 14y agoBecause other parties could work out a person's identity from their regular point of origin/journey route, and thereby invade their privacy.
- sp332 14y agoIt's surprisingly easy to de-anonymize an anonymized dataset. http://arstechnica.com/tech-policy/2009/09/your-secrets-live-online-in-databases-of-ruin/ http://arstechnica.com/tech-policy/2009/09/your-secrets-live... Just because the researchers decided to keep their subject's privacy doesn't mean they should publish the data for any troll to play with.
- gte910h 14y agoIt is nontrivial to make data so anonymous NO ONE can deanonymize it. It's considerably easier to make data anonymous in a way that people acting in good faith to not try to deanonymize it won't realize who is who
- peeters 14y agoIt is nontrivial to make data so anonymous NO ONE can deanonymize it and still preserve the salient information.
- rcthompson 14y agoThere's a limit to how much such data can be truly anonymized, especially when it can be combined with other data sources. Would you be ok with someone relating an "anonymized" database of fingerprints? Of sequenced human genomes? Of credit card transactions? Anonymization is tricky.
- FuzzyDunlop 14y agoWe have those quite a lot in the UK (along various motorways), although they're typically only turned on when congestion starts to build up.
- mitchty 14y agoThe lights in the Twin Cities are the same for the on ramps. Or were rather but same difference.
- baconner 14y agoFor those of you who want to read a bit more about the twin cities traffic metering program there's an entertaining chapter in Numbers Rule Your World that goes through the history and (very lightly) the stats behind it. http://junkcharts.typepad.com/numbersruleyourworld/ http://junkcharts.typepad.com/numbersruleyourworld/
- mikeash 14y agoI'm currently making regular morning and evening roundtrips on I-395 near DC. My northbound segment in the morning is in the same direction as most traffic (into the city), and the entrance is metered. When I do that same segment in the evening, it's the less traveled direction, and there is no metering. This is interesting because the evening drive is often just as slow as the morning drive, even though there's less traffic, something I blame entirely on the lack of entrance metering.
- toast0 14y agoWe do have metering lights (mostly just red and green, one car per cycle) on most of the on ramps in the Bay Area, but a lot of them do not get turned on, even when the freeway is congested and those that do turn on tend to turn off at the end of the official high traffic time, instead of at the end of high traffic (although they usually are adaptive to unscheduled low traffic). In the South Bay Area, there is also usually a major shortage of space to queue behind a traffic meter or to allow for acceleration after a meter. CalTrans knows how to properly design freeways, they do it in Southern California, but up here, they don't show it.
- lostlogin 14y agoThose damn lights are terrible. We have them in Auckland where one authority controls motorway a (freeway) an another the local roads. The lights cause banking up at on ramps, blocking local roads. The motorway flow is improved, sure, but local single lane roads become impassable for hours. The lights just shift the problem here in Auckland.
- stephen_g 14y agoThat's an annoying aspect of trying to retrofit old roads with new tech. Roads designed for ramp metering (in Australia at least) have much longer ramps, both before and after the signal (enough space after for the car to accelerate to the speed of the motorway from being stopped, and before to stop the queue clogging surface streets). But, it could also be a problem with the algorithm they use. The more simple algorithms generally don't take queue length into account, but ALINEA/HERO, which we use in Victoria has queue control.
- corresation 14y agoThe lights just shift the problem here in Auckland. This is exactly their intention, and it's exactly what it does in the Minneapolis area -- it adds a natural saturation point to every onramp, eventually leading to lots of traffic simply using surface roads.
- halis 14y agoOh yeah you mean women?
- deleted 14y ago[deleted]
- DenisM 14y agoIn Seattle I noticed that traffic is always light on Monday, but some places get jammed other days of the week. Apparently, there are many people who don't have to be somewhere on Monday, and those same people chose to drive during rush our on other days of the week. What's up with them anyway? If you don't have to go to work, why drive anywhere during rush hour?
- InclinedPlane 14y agoIt could be that people with somewhat flexible schedules end up going into work later or earlier on Monday than average, spreading out the traffic enough to keep it moving fast. Also, it could be that there are people who don't normally work on Monday, which is actually fairly common in many service industries. Many restaurants are often closed on Mondays, for example.
- goodcanadian 14y agoMoreover, more Mondays and Fridays are taken off either for "sick" leave or vacation. It may only take a small percentage to make a noticeable impact on traffic flow.
- gigantor 14y agoIt may be time we start introducing reverse traffic cameras. Ones that issue fines for not following a minimum speed in peak commute hours for the vehicle that is unquestionably the first in a pack responsible for the jam. Proximity calculations, leading vehicle frequency, trailing vehicle average speed, etc., using existing technology already in place that can be leveraged and innovated on to accurately determine culprits.
- sp332 14y agoDid you read the article? There is no single car that causes a jam. In fact according to previous research http://math.mit.edu/projects/traffic/ http://math.mit.edu/projects/traffic/ (see "Conclusions" at the bottom), even if all cars follow the same rules a jam can still occur. They can also occur in very simple situations like in this video https://www.youtube.com/watch?v=Suugn-p5C1M https://www.youtube.com/watch?v=Suugn-p5C1M
- nollidge 14y agoThe article has nothing to say about needlessly slow drivers, just about traffic volume overall.
- gnu8 14y agoYou can see how the title of the post might give the idea that it was about specific drivers. My first thought when I read it was "I bet it's those god damn hippies hyper-mileing in their priuses", but then I clicked through to the article and it failed to confirm my preconceived opinion.
- nollidge 14y agoSure, so did I, but then I read the article.
- deleted 14y ago[deleted]
- kps 14y agoMany commuters shouldn't have to be on the roads at all. Fiber is cheaper than freeways.
- anigbrowl 14y agoDriverless cars can't come to market fast enough.
- russell 14y agoOne of the purported benefits of driverless cars is that they can drive together in packs. This article would seem to contradict the benefits of that claim. OTOH they would be less prone to the erratic behavior that can create standing waves of congestion.
- sp332 14y agoThey can drive together in packs because they can brake and accelerate in a synchronized way, instead of creating waves of accelerating and braking cars.
- DanBC 14y agoVolvo has been testing a "road train". (http://green.autoblog.com/2012/09/18/volvo-finishes-satre-project-road-train-works/ http://green.autoblog.com/2012/09/18/volvo-finishes-satre-pr...) (http://www.bbc.co.uk/news/technology-18248841 http://www.bbc.co.uk/news/technology-18248841) It's an interesting idea, even though not as advanced as Google's car. I'd like to see results of testing, especially for the standing wave phenomenon, but also how a truck driver copes with driving "a vehicle" that is many times longer than what they're used to driving.
- gregsq 14y agoDriving on lengthy highways in Australia is interesting, at least in the state of Victoria, where enforcement of the speed limit is very strict. The limits of 100kmh and 110kmh are enforced within a mandated speedometer error limit that's very tight for new cars. Older ones have looser accuracy, predating the legislation that enforces the error limit. One if the consequences is that on long stretches of road, cars that are very slightly quicker catch up with others. Then, because there's safety in numbers, and because other cars normalise speed through a kind of meaning speed check, clusters form. Overtaking is tantamount to breaking the law, though some attempt to creep by, leading to reduced distance between vehicles, and increased stress for drivers due to reduced reaction time. Under these kind of circumstances, a strong argument could be made for driverless cars, if only to avoid the increased potential for collision due to driver error. And it demonstrates for one embedded in the packs that form, the kind of experience that we can expect.
- gbadman 14y agoI've always felt that driving in traffic is a sort of prisoner's dilemma. Consider a two-lane highway that splits into two directions, a very popular direction and an unpopular direction. Inevitably, we will see a group of people who will wait to the last second to cut into the popular lane. These late-comers cause two problems: 1) people to hit the brakes who get cut off in the popular lane, and 2) people to hit the brakes in the unpopular lane who are forced to slow down to allow the selfish drivers to merge. When I take the generous approach and wait in line, I hate people who cut in. On the other hand, I find myself clever for cutting in at the last second and saving time when I take that approach. I'm still not sure which approach is 'right'. All I know is that the latter will increase overall delays while doing the former will have little to no impact on overall delays but a major impact on my own. Traffic is a pretty interesting subject.
- maxerickson 14y agoWhen you say major impact, do you mean something like 45 seconds, or something else? I'm asking in all seriousness, I have no idea what sort of traffic you are driving in.
- deleted 14y ago[deleted]
- kgermino 14y agoNot sure where gbadman is, but a similiar situation I often see at the circle interchange in Chicago waiting in line (as you should do in that case) can easily cost you several minutes.
- gbadman 14y agoI'm in Montreal. We have a serious traffic problem during morning and evening rush hours. In fact, TomTom has put our city at #4 in North America for worst traffic and it seems #1 for both morning and evening traffic peaks [1]. Two places that I can think of this being brutal are taking Decarie Blvd exit from Decarie North and taking the 20W exit off of the 13S. I'm sure that are some other pretty good examples out there. 1: http://www.tomtom.com/lib/doc/congestionindex/2012-1003-TomTom-Congestion-Index-2012-Q2-namerica-mi.pdf http://www.tomtom.com/lib/doc/congestionindex/2012-1003-TomT...
- ChuckMcM 14y agoOne of the things I really like about this study is that it captures not only road congestion but where the drivers enter into, and exit, the freeway system. And it reconfirmed for me yet again that starting/ending in Sunnyvale is reasonably optimized for working in the 'valley' part of Silicon Valley.
- jmspring 14y agoThe problem I have is the study didn't fully factor in road layout/design. Highway 85 here in the Valley spans from the south Valley up to 101 in Mountain View. Within months of opening, it was a recurring traffic jam. Boom or bust in the valley, traffic let up a little in the bust, but the road is congested pretty much from 6:30am until 9:30/10am in the morning. Intersections of 85/280/101/237 at the north end impact traffic northbound in the morning. 85/280 impacts southbound in the evening. Again - patterns persisted during both the last two booms and busts. It is more than just a "small group of drivers".
- sadfaceunread 14y agoThis research was published with supporting information in an open access journal (Scientific Reports [Part of Nature Publishing Group]). See the full text for more. http://www.nature.com/srep/2012/121220/srep01001/full/srep01001.html http://www.nature.com/srep/2012/121220/srep01001/full/srep01...
- ryusage 14y agoReminds me of an interesting site[1] I came across a while ago, in which the guy argues very convincingly that traffic jams occur as waves, which are started when even a single car does something to cause the car behind them to slow down (avoiding something, stopping to merge, etc). If it's non-trivial, then that will begin a chain reaction - a wave propagating through a medium of cars. The severity of that effect is directly proportional to the density of the medium/traffic. Given that perspective, metering lights to reduce density seem like exactly the right solution. [1] http://trafficwaves.org http://trafficwaves.org
- defrost 14y agoThe first time I heard about traffic waves and the use of active feedback to eliminate traffic jams was from [Prof. John Mahoney](http://www.asap.unimelb.edu.au/bsparcs/aasmemoirs/mahony.htm http://www.asap.unimelb.edu.au/bsparcs/aasmemoirs/mahony.htm) in 1984, he gave two 45 minute lectures on the subject and later in the year posed two related unsolved problems in the area on our exams, we were undergraduates at the time but that was typical of him to make up exams at the last minute and pack them with current problems from either current literature or his in-tray.
- Lost_BiomedE 14y agoMy father, in grad school, worked in a lab with a guy who pioneered a lot of this research. He showed the coil like action of these waves and how they created wrecks. Here are some other things I thought were cool: He calculated the risk of changing lanes on a highway and estimated how much people valued their lives in dollars (usually fractions thereof) based on this one criteria. He drove vehicles into lakes to study the escape from such a vehicle. He tracked the eyes of truckers and found that their eyes would fall to the front of the hood and dart up a few times about 30-45s before they fell asleep and wrecked. Another guy tried to make a talking highway by varying the distance of groves and marks on the road. Just thought some might find this stuff interesting or amusing.
- gwillen 14y agoI'd be curious if you have data on the risk of lane-changes. (Knowing how dangerous they are would probably cause me to do fewer of them.)
- jakozaur 14y agoDynamic pricing might be a good solutions (with reasonable maximal prices). However, it would be hard to introduce them because of public pressure.
- shiftpgdn 14y agoWe have dynamically price toll roads and HOV lanes in Houston. I don't recall many objections when they were implemented.
- chii 14y agowhy would dynamically pricing tolls cause less traffic? Especially in the morning rush hour - you gotta get to some place by a specific time, you have to pay the toll no matter what it was (with reasonal maximal prices of course). its only when there is an unreasonable maximal price (or no maximal price) that people's behaviour would change - imagine a toll of $500 during peak. It would put off people from going on the road.
- jakozaur 14y agoWell that's true, but the article already points that taking a few % drivers out of roads could make a huge difference. See: http://www.ted.com/talks/jonas_eliasson_how_to_solve_traffic_jams.html http://www.ted.com/talks/jonas_eliasson_how_to_solve_traffic... You don't need anywhere 500$, most likely 2-5$ toll is good enough.
- sunnybythesea 14y agoI yearn for the day when driver-less cars become the norm. But then, I'm sure the same people will find ways to jailbreak the software and enable reckless driving behavior :(
- geoka9 14y agoWhy wait for driverless cars when there's public transport which lets you enjoy the same benefits? Isn't it sad how pefectly fine we're with hauling 2000+ lbs of hardware just to get 150 lbs of flesh from point A to point B in the morning and back in the afternoon.
- jordanthoms 14y agothe "same benefits", so long as you, y'know, ignore all the benefits of cars.
- chii 14y agothe single biggest downside of public transport is that you don't control the schedule (nor where it goes - but lets ignore that for now). A driverless car is a taxi that's cheap and effective. You don't have to park it, you don't have to figure out the route. You just hail one, get in and type in the destination. Its sane public transport.
- jeltz 14y agoActually the schedule part rarely matter for commuting to work since those routes usually have a high density of buses/trains. In Stockholm during rush hour the subway arrive every 1 to 5 minutes, commuter trains every 7 to 15 minutes, buses usually every 3 to 15 minutes. Not controlling the destination usually matters more since that means you may have to change train or bus several times.
- dmfdmf 14y agoI'd like to see a website where I can enter my home address and work address and it will generate a chart of leave and arrival times for each day of the week based on prevailing and constantly measured and updated typical traffic patterns with accident-jams removed. In my experience traffic patterns, even without accidents, are highly non-linear and leaving 10 minutes early or later can drastically reduce your drive time. You could even have it rank different routes so that on any given day of the week you might take a different route and leave at a different time to minimize your drive time and increase the probability of arriving on time. Metering lights have their use but are limited in how long they can hold up a car whereas if I am at home or work its no problem to adjust my schedule +/- 10 minutes or more to avoid a jam. As more people signed up for such a site it would also become more efficient since it could take into account where and when people actually want to go in its planning calcs.
- deleted 14y ago[deleted]
- anonymousDan 14y agoThe problem with any such site is that if it became sufficiently popular it would result in feedback effects that might destroy its predictions.
- bo1024 14y agoOr it could do better -- dispense predictions/instructions so as to ensure an even distribution of traffic (e.g. by randomization).
- kragen 14y agoAn unethical freemium model for such a site: dispense instructions to ensure an even distribution of traffic to free users, but provide a purely optimal path for paying users, perhaps even making suggestions to free users to move them out of the way.
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- corresation 14y agoThe title of the submission is deeply misleading, though it follows some rather ridiculous claims in the article- Instead, they come from a few outlying neighborhoods and travel long distances together in the same direction like schools of fish -- clogging up not only the roads they drive on, but also everyone else's. The notion that they are to blame is asinine. A highway is being utilized beyond capacity, but picking out any group on the highway adds dramatic narrative yet little insight. The suggestion that you remove "just 1%" is surprisingly naive as well, reminding me a bit of this Onion piece - http://www.theonion.com/articles/report-98-percent-of-us-commuters-favor-public-tra,1434/ http://www.theonion.com/articles/report-98-percent-of-us-com... If the highway had less utilization, it would cause many who use mass transit (like light rail) to choose the highway. Rinse repeat. It is how highways in virtually every metropolitan area eventually reach a point of saturation, that new point becoming the natural balance.
- thrownaway2424 14y agoRight. Which is why the only sane way to deal with traffic is to ramp up the tolls until the utilization falls below 90% or whatever the threshold is. I don't care if the rush hour toll on the Bay Bridge is $50. It will cost less, overall, than having thousands of people stuck in traffic for hours.
- MereInterest 14y agoOr, you know, investing in infrastructure where it is needed.
- hnriot 14y agoI think you're exaggerating somewhat disingenuously. I commute over the bay bridge and it generally flows well, "stuck for hours" just isn't realistic. It's already $5-$7 which seems quite enough given that I already pay local taxes which are supposed to be for infrastructure.
- Nitramp 14y agoAs there's no alternative in public transport (that I'm aware of), if you charge $50 to cross the bridge, you will make it impossible to work in SF for people living North and earning below a certain threshold. So these people will either have to move, or find a different job. That seems like a somewhat extreme outcome. Offering attractive alternatives to commuting by car might be a better way to reduce congestion on the roads.
- JonnieCache 14y agoIsn't this a strong argument for better buses? I guess that's not really the thing if one works in the valley with a huge salary... Surely the geek bus would be a cool place to be though?
- chii 14y agothe problem with public transport isn't that its uncool, but that you still ahve the "last mile" problem. Also, you have to plan your life around the transport, where as if you owned your own car, you dont need to do so. THe best solution isn't better public transport, but self driving cars that you can get ondemand (but don't own).
- anthonyb 14y agoNot necessarily. Cars still use a large amount of land area per person, even if they're self driving and don't need many car parks (I disagree with that last part though, considering commute patterns). Take a look at http://carfree.com/ http://carfree.com/ for a good overview of what could be done with public transport, as well as all of the unseen issues with car use.
- jeltz 14y agoThe last mile problem is mostly caused by poor urban planning, where the urban planners did not consider future building of public transport. And in Sweden this poor urban planning was basically caused by people thinking public transport was uncool.
- sliverstorm 14y agoTHe best solution isn't better public transport I disagree. - If public transport arrives and departs often enough, you don't have to plan your life around the transport. - If the public transport network is large enough, you can eliminate the "last mile" problem, either by making it short enough to walk quickly or by connecting backbones to local distribution. Classic example, train + bus. Of course the Bay Area has nothing close to this kind of network, but you said "the best solution", and I'm pretty convinced an idealized public transport system is much better than driverless cars. Superior passenger density, superior fuel efficiency, superior materials usage, etc.
- malachismith 14y agoSo, basically, the suburbs are the problem?
- cagey 14y agoThe first two paragraphs of this article are crap, typical of the "journalism" of today. A groundbreaking study ... has pinpointed a small group of drivers making Bay Area freeways miserable for the rest of us... You mean the other drivers, incremental vehicles coming from other sources, are simply not contributing to traffic misery? Who knew?! At least the solution is both obvious and simple: the "small group of drivers" should clearly be "gotten rid of" so the misery of the virtuous is removed. Line 'em up against the wall... ...they come from a few outlying neighborhoods and travel long distances together in the same direction like schools of fish -- clogging up not only the roads they drive on, but also everyone else's. You mean, they're "everyone else's" roads, and these cheeky interlopers are taking what rightfully belongs (only) to "everyone else"? And the other commuter vehicles are not traveling together "like schools of fish"? Why do the (government) planning departments bear NO responsibility for the results of _their_ decisions? Specifically, they have the final say regarding where houses, apartments, roads, shopping centers, ad infinitum, are built. Yet the ultimate fault is with people who simply chose to live in certain locations, rather than bad capacity planning prior to their homes being approved to be built?
- jeltz 14y agoThe rest of the article discuss government solutions and metered lights though. Misleading, populist headlines and first paragraphs are staple of modern journalism.
- Thrall 14y ago"These commuters .. travel long distances together in the same direction like schools of fish" Sounds like what they need is a train, tram or bus.
- thrownaway2424 14y agoReactionary boomers in Marin county have been slow-rolling the regional rail plan (SMART) for decades. Don't hold your breath. If SMART ever comes into any kind of decent service it should relieve a significant demand among north bay-to-sf weekday commuters. Note, however, that SMART service to Larkspur Ferry is "planned" and "phase 2" which means probably not in my lifetime.
- swampthing 14y agoPretty interesting. I wonder if any non-technical approaches have been tried - like educating drivers to move to a right-side lane if they're slow. At least on the 101, it seems like so much of the congestion would be alleviated if slow people stayed out of the left-side lanes. It'd be safer too since it'd remove the incentive for drivers to weave through traffic.
- brini 14y ago"This has enormous potential," said study co-author Alex Bayen, a UC Berkeley professor of electrical engineering and computer science. "These findings are going to come into practice in the near future. This is not just a scientific study." ``... not just a scientific study.'' Reinforce engineering v. science stereotypes much?
- Nitramp 14y agoAn alternative are variable speed limit systems: http://en.wikipedia.org/wiki/Speed_limit#Variable_speed_limits http://en.wikipedia.org/wiki/Speed_limit#Variable_speed_limi... They can be used to slow down cars heading into a traffic jam to reduce the arrival rate so the traffic jam can dissolve. Roads with a lower speed limit also fit more cars (need less safety distance) - driving slower means less traffic, so traffic jams can be avoided by reducing the speed limit. These systems are very wide spread in Germany, covering most Autobahns around major cities.