Want To Design Smarter Intersections? Use Less Control, Not More.

from the embrace-the-chaos dept

IBM The topic of this post is sponsored by IBM. Read more about building a smarter planet on the IBM A Smarter Planet Blog. Of course, the content of this post consists entirely of the thoughts and opinions of the author and not of IBM.

Drivers in the United States are faced with a constant barrage of traffic signs, lights and signals all meant to navigate them safely through the sea of cars, pedestrians and bicycles without incident. Furthermore, US drivers are faced with an increasing array of laws that prohibit a multitude of things like speaking on the cell phone while driving, even though studies have shown that roads are not necessarily safer. Red light cameras have been installed under the guise of making intersections “safer,” even though, like the cell phone bans, study after study has shown that these cameras do little more than provide a revenue stream for the cities that employ them. The problem with using signs and fines to enforce driving behavior is that they usually attack the symptoms of bad driving, rather than the bad driving itself. After all, playing video games while driving has always been a bad idea, even before it was explicitly forbidden by law. Similarly, by teaching drivers to constantly monitor their speed and look out for red lights, they are preoccupied with the wrong things — they should be watching the road and traffic around them instead.

Instead of trying to micromanage every aspect of safe driving with signs, signals and laws, a better approach would be to utilize what should be the smartest part of the car — the driver. Just like a poorly designed door needs a sign to tell you whether or not to “push” or “pull” it, a poorly designed intersection needs to tell you when to stop or go. So, a better way to design an intersection seems counterintuitive: reduce the number of signs and signals. Back in 2003, in the Dutch town of Drachten, traffic engineer Hans Monderman replaced red light intersections with traffic roundabouts with reduced signage. Moving through the intersection, there are almost no signals or signs to direct the traffic at all. As a result, drivers, pedestrians and cyclists pay more heed to the actual traffic patterns within the circle. So, rather than blindly following traffic signals, they proceed much more carefully and make eye contact with each other as they make their way through the intersection. Traffic flows better now; gridlock is a rarity. Most importantly, six years after the improvements, Drachten is safer — prior to the roundabout, there were over eight accidents per year, after the roundabout was installed and traffic signs and signals removed, less than two. By making traffic seem more chaotic, it is actually made safer.

Of course, any new approach has its doubters — after all, intersections in Asia are infamously chaotic:

However, upon closer inspection, this seemingly chaotic traffic pattern actually works surprisingly well. Pedestrians, cyclists, cars and buses all coexist in relative chaotic harmony. With the addition on one simple rule, like a roundabout, it could possibly work even better — but, to try and control everything with traffic signals would definitely disrupt the flow. As our cities and towns get more and more congested, embracing this concept of “shared space” will become increasingly important. After all, traffic improvements aren’t just good for cars — they make cities more livable for pedestrians and cyclists too. Elsewhere, according to Wired, when the town of West Palm Beach converted “several wide thoroughfares into narrow two-way streets, traffic slowed so much that people felt it was safe to walk there. The increase in pedestrian traffic attracted new shops and apartment buildings.”

Recently, to celebrate 50 years of automobile safety improvements, the Insurance Institute for Highway Safety crashed a 2009 Chevy Malibu with a 1959 Chevy Bel Air. The results were impressive; the theoretical occupants of the 2009 vehicle would be able to walk away relatively unscathed compared to their unfortunate cohorts in the Bel Air. However, although modern autos do a great job of protecting vehicle occupants in case of an accident, a smart city with well-designed traffic systems could help to avoid such accidents in the first place.

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Comments on “Want To Design Smarter Intersections? Use Less Control, Not More.”

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Anonymous Coward says:

The problem with rotaries is that some people don’t understand that they need to yield to the traffic in the rotary. There was a rotaries nearby that always backed up on the local streets because the highway entrances (the rotary was above a divided highway) would supply a constant stream of cars to the point where it took a long time for a space to open up enough for someone on the local street to get in. They replaced the whole thing with lights and now the backups are much, much smaller, if they occur at all.

I do agree that it seems like every traffic problem is tackled by adding more lights and that’s not always the right decision. I think maybe by adding more intelligent lights would work better.

Chuck (profile) says:

Re: Re:

Thing is, that happens daily, and with very little accidents. Everyone is conceited, yet because of that, they make sure they don’t crash. You’ll be amazed if you were in a taxi going into a tunnel in China. 8 toll booth lanes going into a 2 lane tunnel like a maniac. I’m sure if a crash happened there, all the other drivers would beat the crap outta whoever crashed.

Anonymous Coward says:

Re: Re: Re:

Yes, I’m sure it happens daily with little accidents. /sarcasm

Without a traffic safety study on the intersection I won’t believe it. The traffic there was extremely light and it mostly involves motorists and bicyclists. This is not a solution for any problem intersection you run into.

Also, when those bikes are hit, the severity of those accidents is going to be through the roof.

You can find a 3 minute clip of someone weaving through traffic on the wrong side of the road. No one would be crazy enough to suggest that we can improve our efficiency by all the traffic doing that.

Derek Kerton (profile) says:

Re: Re:

What’s important to me is the rate of flow. How many cars can a chaotic intersection process versus a stop-light controlled intersection versus a roundabout.

I have read that the roundabout wins. It costs more to deploy up front, but lowers maintenance costs, and handles higher volumes of traffic. It is also less frustrating, requires fewer idling vehicles, and is “automatically” flexible for different times of day and traffic loads.

Willton says:

Re: Re: Re:

What’s important to me is the rate of flow. How many cars can a chaotic intersection process versus a stop-light controlled intersection versus a roundabout.

I have read that the roundabout wins. It costs more to deploy up front, but lowers maintenance costs, and handles higher volumes of traffic. It is also less frustrating, requires fewer idling vehicles, and is “automatically” flexible for different times of day and traffic loads.

They also occupy far more real estate compared to a stop-light intersection, which can be an inefficient use of that land in areas where commercial or residential buildings placed on said land make said land more valuable. The traffic light intersection is simpler and uses a smaller amount of space than a roundabout or traffic circle.

Amaress says:

Round-abouts are good when there isn’t a whole lot of traffic from any direction. After a while you end up with multi-lanes and people get confused and scared and sit at the entrance for far, far longer than they should…

Almost all of the intersections on one side of my city are roundabouts, and the other side is traffic signals. The side with the roundabouts is far faster to navigate through until rush hour, then the side with the lights is faster.

Anonymous Coward says:

Re: Re:

That’s what traffic engineering predicts for roundabouts. They are far better at moving traffic until you get about 1100 cars in conflict (for example 700 in the circle and 400 wanting to enter from an approach). Then they are far, far worse than a signal.

So if you have an area with low population growth and not much traffic, a roundabout can be a great solution (and roundabouts reduce conflict points (and thus collisions) from 32 to 8). But it requires traffic studies to determine that.

Derek Kerton (profile) says:

Re: Re: Re:

The problem I’ve found with roundabouts is when one of four inbound roads delivers a far greater load than the others. What happens is that this feeder begins to dominate the roundabout. In some senses, this is a good natural solution, since that inbound feeder NEEDS to get more relief. However, if it delivers a non-stop, steady feed of cars, the next two feeders will have no gaps into which they can insert their cars.

Jon B. (profile) says:


Ok, so I watched the video…

The traffic is really freaking slow. I can’t imagine that working in my town full of 25, 35, and 45 mph roads. It also doesn’t explain much of how it works. To me, it looks like it’s just “go really slow and deliberately plow your way through”, or a codified form of “asshole driving”.

Also clicked on the wired article. tl;dr, with too much narrative. I would like a simple quick explanation, not a novella.

So, this is the 5th or 6th article I’ve read on these subjects, but I still have no idea how specifically any of these alternatives work. I also don’t see, quantifiably, how they would be better than the system of triggered red lights in my area.

Now, I do agree then I’ve seen many, many, many streetlights go up in places where a stop sign would do fine, and many 4-way stops where a two way worked fine, etc. I also agree the red-light cameras and cell phone laws are incredibly counterproductive and are usually just revenue grabs. So, yes, fewer laws, less control, better roads. But I don’t see how the revolutionary changes would help my hometown.

Thought it’s not linked here, I think I have seen a video of the Dutch roundabout (no not that video, the other one) and it looks like it just turned the intersection into a bunch of right turns. Which is fine, but it would involve digging up a crapload of real estate for a given intersection.

TW Burger (profile) says:

Safety and Revenue Streams

I am a little bit tired of the constant “Red light cameras do nothing to stop accidents and are just revenue streams for local government” arguments. It may be correct that traffic cameras so little or nothing to stop drivers’ stupidity but making them pay for their sins does provide some compensation for the social costs (hospitals, loss of wages) bad drivers cause.

As for the video: The Chinese may be much better at the social skills required to handle a crowded and unregulated situation like the intersection shown. Try a traffic design like that in Akron, Winnipeg, or, God forbid, Los Angeles, and the result would be apocalyptic.

Anonymous Coward says:

Re: Safety and Revenue Streams

Exactly. China’s drivers, pedestrians, and all in between are very self organizing, and very good at operate within a chaotic system. To do that requires a certain amount of natural give and take, and flexibility in approach.

Americans in particular are way to selfish to use such a system. The result would be gridlock to the n’th degree.

Anonymous Coward says:

Re: Re: Safety and Revenue Streams

“Americans in particular are way to selfish to use such a system. The result would be gridlock to the n’th degree.”

So basically, if we implemented this system in Los Angeles nothing would change. The 405 parking lot, I mean, freeway would be the same as it is now.

Anonymous Coward says:

Re: Re: Re: Safety and Revenue Streams

No, it would be worse.

In China, lanes are a suggestion, not a fact. So a 4 lane freeway in America might be 6 lanes by chinese rules, with bikes, scooters, hand drawn carts the size of cars, small engine farm tractor truck things, and all other manner of “things that move” all over the place.

If American started to ignore the rules that they do follow, things would go to crap pretty fast. Can you say “road rage”?

Luke_Stackwalker says:

Re: Safety and Revenue Streams

I concur. Having consulted at a photo-enforcement company, I quickly learned that this is a no-win business model. The fines are a strong incentive to NOT run the red light. So much so that even the warning signs (with no actual cameras) reduced red light running.

The biz model problem is that these installations cost lots of money and as drivers learn which intersections are enforced, the revenue stream dries up (meaning less running of red lights, meaning less accidents in the normal course of action), thus the problems with adjusting yellow light times to drive revenue.

The company I wored with DID NOT and COULD NOT interface with the signalling system. It had to use external sensing of the lights, so only the traffic department could tweak the timing. Yes, if the lights are too short that is a problem, but that is another story about government corruption, not safety or enforcement!

But I digress.

Long story short, ENFORCEMENT period does reduce runners, photo enforcement done correctly is just that, enforcement.

fogbugzd (profile) says:


One reason the traffic flow in the video works is that the actual traffic flow is rather low for the size of the street.

Another significant factor in the video is the mix of vehicles. Many of them are non-motorized, and even many of the motorized ones are underpowered moped types of bikes. Trying to impose any type of traffic control system in that type of environment would be a nightmare.

Anonymous Coward says:

Re: congestion


if you’ve ever been through MIA, DC, ATL, NYC or any other major city while the power is out, you know that this traffic example is merely anecdotal.

shit, there are people who get their masters solely in traffic management and they use complex algorithms to reduce traffic. 1 stupid youtube video of a tiny town in china is not the “exemplary solution”.

Anonymous Coward says:

You know, in the states, very large busy 4 way stops can operate almost like this. When the intersections get large and constantly stacked with cars, the stop sign yielding rules get rather complicated and people depend on telepathy and improvisation to navigate the intersection. Of course in a place where this isnt the norm, there are lots of visitors to the intersection who have no idea of how to peacefully conduct themselves in this context and make it exceptionally dangerous. But I generally think it works OK, as long as you dont have asshats who think they have to come to a complete stop and wait 5 seconds.

Urza9814 says:

Wouldn't work.

I was in Nantucket over the summer with some friends, and they have roundabouts on the busiest intersections there. Now, Nantucket isn’t that big of a place, and traffic is never that bad, but you can still be waiting there 10-20 minutes to get onto the roundabout if there’s a good stream of traffic in one direction. So in an apparent attempt to solve that they altered it a bit so it’s two lanes in some parts and only one lane in others and generally a confusing mess. If you’re going straight along the main road in one direction you get a special lane that bypasses the roundabout but if you’re coming in the other direction you don’t. But if you’re turning right from one of the side directions there’s a special lane that lets you bypass it as well…and it’s _still_ damn near impossible to get into it.

Yes, roundabouts are the most efficient in terms of cars in and out per hour. But there comes a point where you have to sacrifice efficiency so it doesn’t take an hour to make a right turn.

To use a computer analogy: The most efficient computer would be one that doesn’t have any input or output. But that isn’t very _useful_, is it?

Ryan says:

I hate lights...

Countless minutes Ive sat wasting gas at a light, not because other cars were going, but just because of timers or what not.

If they reprogrammed red lights, to see vehicles by weight and speed to find momentum, then let the ones with more momentum go first (until a certain time period) then millions of dollars in gas and frustration would be saved, let alone time.

So many times I have been cruising at 40 and the light turns red in front of me to let a stopped car go, and I was the only car. If the light had known to wait 5 seconds then it would have saved whatever amount of gas it takes me to get back to 40mph

senshikaze (profile) says:

Okay, two questions:
1)Am I the only one who thinks IBM’ “Smarter Planet” commercials are mis-targeted. I mean, what are they selling? I am not going to buy a mainframe because it might help traffic jams in China or crime in New York. So what is the point. What are they gaining by showing me, a mid-twenties, male in the Southern part of the USA these ads on all the great things IBM may or may not be doing? As far as I can see they gain nothing. (of course, since I don’t let my buying habits sway on how many times I saw an ad during a college football game, I am not the best “consumer”. Some would even say I am a bad Capitalist.(I am) I just don’t understand the point of ads of any kind, and don’t allow them when using the ‘net. Word of mouth is worth more to me than 30 seconds of flashy colors)

2)Why do you have a razor blade with two blood drops for the icon of “Bleeding Edge” articles? I realize the symbolism, but doesn’t it seem a bit… tasteless? Just saying.

and, no, I have nothing to comment on the actual story 🙂

NullOp says:


There is no way in Hell anyone is going to reduce signage in this country! And certainly no way in Hell anyone is going to kill a revenue stream like traffic cameras! This is the country of law & order because we said so! It doesn’t matte what makes sense or whats been proven somewhere, some lawyer will prove all this was done to persecute HIS CLIENT!

Anonymous Coward says:

Micromanagement sucks, and usually leads to revolt.

Recently, I picked up a copy of:
“Keeping The Millennials: Why Companies Are Losing Billions in Turnover to This Generation- and What to Do About It” by by Joanne Sujansky, Jan Ferri-Reed.

Now normally, anyone with the last name Sujansky would immediately bring to mind the last name of Sinofsky, but that shouldn’t be the reason why you buy the book. In fact, Jan Ferri-Reed kinda looks like “Conny Booolmer”, if you happen to squint your eyes just the right way and tilt your head just so, you’ll see it.

But Joanne and Jan make very valid points in their book. Perhaps you’re in a company where it seems at times you get a group of super smart people (or at least they think they’re smart) together and all of a sudden they start picking on you and it’s like elementary school all over again. The biggest problem is the high achievers. You know the ones. They’ve never been told “No” in their life, got into Harvard, CalTech, Stanford, SUNY and somehow they didn’t decide they had the balls to get aboard the Train Wreck bound for NYC when they will finally be told “No” when they decide to take the US Financial System for a ride or something.

The GOVERNMENT needs desperately to say NO to a number of things. These things include finding ways around laws and not adhering to the SPIRIT OF LAWS which they were written.

I’m a little concerned when someone says they need less control and not more, because there’s probably a few things that need to be addressed. First off, as of today, laws were written for human enforcement, and not automated servers attached to redlight cams. This is important because a human can discern a number of factors better than any redlight camera. When you take the human out of the equation, the rules written for human-enforcement should not apply. Instead, the enforcement model should include other factors such as habitual offenders. Does the automated solution support habitual offenders?

Secondly, was the intersection marked properly? Often, those who are unfamiliar to the area have no knowledge of a red-light camera at an intersection. Many times, the local enforcement omits this.

In fact, a guy down the street from a friend I regularly visit frequently performs revenue activities in his driveway. (I believe the house is owned by a Denver City cop, as at times I have observed a Lieutenant or Sergent labeled car outside his house. Apparently, he wasn’t good enough to graduate from the same school as my Cousin or Father, who run CIA and FBI offices, respectively, because Denver has quite lax hiring policies where you could have a felony on your record and be hired by Denver PD, or so I’m told.)

Anyways, I’ve actually ran into this a few times with a level of awe.

It’s around the 100 and 200 block of Monaco Parkway. Maybe 195. Not sure.

Anyways, some asshole lives in an area where city planners have designated the safe speed to be less than the actual speed of drivers, which is fine for Hickenlooper because he can do something with the money.

Now, you’re probably wondering why this matters.

Well, oftentimes, City and Traffic Planners get together in some brewhaha and determine the maximum speed in any given area.

Often, someone tries to show his power by bringing a photo-radar van in front of his house and saying Hey, I made $2M for you, Mayor, will you promote me?

Listen here:
Automation of law enforcement is an infringement on people’s rights because law enforcement laws were made with a human in mind. Not a computer.

I’m surprised that more unionized traffic cops across the country are not more angry at this.

Anonymous Coward says:


Years ago I worked for a company that did mostly international business with independent business men around the world. One of our customers was from Taiwan and when he came to the US we would pick him up at the airport, take him out to dinner, etc. and I remember riding along with him in the car once and we stopped at a red light and waited even though there were no other cars around. He asked why we stopped and when we explained that we had to because the light was red he was just flabbergasted that we would be so silly.

A few months later it was my turn to go visit him in Taiwan (technical support) and found that in his area red lights just suggested that you should yield to cars with green lights and people rarely stopped for them. And you know what? It worked pretty well. Yes, it was chaotic but they managed to put a lot more traffic through the streets than would have been possible on equivalent US streets. In fact, the traffic was even heavier than shown in the video above. I was there for several weeks and never saw an accident and would have probably had difficulty believing how well it worked if I hadn’t seen it myself. Now I’m also a former driving instructor who had a reputation for giving pretty tough driving tests so you can imagine how surprised I was.

R. Miles (profile) says:

Roundabouts aren't always the answer, but...

…they’re a fantastic start.

I hail from Carmel, IN, where the mayor insists a roundabout be placed at (nearly) every intersection. It first started out with a few here and there, but the growth has been explosive since.

The major impact has been Keystone Avenue (still under construction) in which all points between 96th St. and 131st St. are to include “tear drop” roundabouts over the primary thruway.

I absolutely love it. No stopping, save for the few cars already in the roundabout, but less than the old 2+ minute traffic system.

The changes were so dynamic, the state of Indiana is now proposing they be added on a parallel street, which is one of (if not the) busiest roads. Unfortunately, I see no changes coming anytime soon despite every benefit to the contrary.

However, there is a caveat to using a roundabout and several have touched base with them. Of course, we’re right back to the driver being at fault for failing to navigate it properly.

The “chain o’ cars” often brought up is the downside to a roundabout, in which cross traffic must wait at times longer than what a traffic system had subjected them to previously.

A simply “yield” sign does no good, because the crux is the yielding is to the cars in the roundabout. Removing those who are clueless, it’s this issue which allows the stream to perpetuate once it gets going. People simply don’t yield and “rush” the line so they are the ones who are to be yielded.

But, as I said, it’s a great start. I’ve noticed a huge increase on roads utilizing roundabouts vs. a neighboring parallel road. It seems people do desire a road without restrictions. Despite the changed signal timing of the parallel road, it’s becoming more vacant (which is great for me!).

With a bit more proper education, I do believe roundabouts are a great way to improve traffic. I hit two every day, and wish there were more.

Now, if only we can address those complete idiots who either stop in them or change lanes while navigating them.

Chillienet (profile) says:

roundabout city

I live in Canberra, Australia. It’s a city often referred to by other Australians as roundabout city. I would love to be able to say that all of these roundabouts make driving safer and more efficient but (I am speaking as a tradesman) Canberra is a city full of politicians and public servants, none of which, IMHO, should ever be allowed behind the wheel of a car.

Maybe with out the roundabouts traffic would be a nightmare, guess I’ll never know.

Chris says:

I agree with this

I spent a few weeks in Egypt a few years back. The country is known for chaotic driving, and there are NO lights or signs for the most part, and those that are present are essentially ignored (just as they ignore the lines painted on the road).

Now I did see plenty of evidence that many cars experince small minor hits (hardly a car without a few scraps or small dents in fenders/bummpers) I did not see any major accidents. With the huge number of cars, trucks, buses, motorbikes, bicyles, donkey and pedestrians, I expected to see more trouble.

It shocked me that things moved with a strange harmony. Pedestrians running across the road as they pleased and cars just moving around them, running 5 lanes in a 3 lane road (even more fun when you are the pedestrian, just go, do not stop and the cars will just miss you! :)). Traffic was slow in many places (gets really bad with construction) but you never find your self just sitting still very often, you are always moving at least 10 mph. This allowed us to move across Cairo far faster then I can move across Phoenix (current city of residence) or any other major US city I have been in.

While I can be a bit scary when sitting in a taxi that is weaving in and out and cars are moving with no sense of logic, the system works, the drivers there are very skilled and pay attention. They actually recommend you use hired drivers as most people not used to the area are unable to effectively drive there.

Joëlle says:

I think you’re right about what you said but the main thing that makes this plan work or fail is if the drivers are ‘programmed’ to follow the rules and signs or actually interact with the other traffic.
Interaction is so very important in chaotic traffic!

I myself am a 19 year old girl that has been riding a bicycle all her life(I live in the netherlands), over here you have a lot of roundabouts and few rules for them, but what you need the most is the ability to estimate if people are going to let you first or if you have to stop. Otherwise you’ll sure get in an accident.

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