Monday, July 02, 2012

Busy Intersection: No Traffic Lights v. Traffic Lights



The video above shows the same intersection in Auckland, New Zealand at the same time of day.  The video on the left shows the traffic moving through the intersection without traffic signals following a power outage, and the video on the right show traffic the next day after power was restored and the traffic lights were working again. 

HT: Jake W.

Related quote from Dylan Brice: "Developments in traffic engineering show that measures aimed at making roads safer (such as road signs, traffic lights) actually make roads less safe. They signal to drivers that it’s OK not to think through the risks of their behavior."

26 Comments:

At 7/02/2012 2:47 PM, Blogger yamahaeleven said...

Be interesting to know statistics about accident rates comparing controlled and uncontrolled intersections with similar traffic flows.

 
At 7/02/2012 3:28 PM, Blogger Methinks said...

Fascinating!

One of the first things I noticed about Egypt is there aren't a lot of traffic lights even in the cities. Where they have them, they are largely ignored and traffic moves along fine. Even pedestrians cross the street by stepping into traffic and holding out their hands. Cars yield. People and cars try to watch where they're going. It all just works out.

 
At 7/02/2012 3:35 PM, Blogger Ken said...

Lots of data supports the idea that less control or data in the form of lights and signs, etc. are good for traffic flow. Many faile to realize that drivers are thinking beings able to make decisions. Many also fail to realize that the more signs, lights, and road markings they put up, the more distractions drivers have from paying attention to what's in front of them.

 
At 7/02/2012 3:41 PM, Blogger morganovich said...

methinks-

i noticed the same thing. cairo drivers do not even look at lights. i have long held that if you just watched the traffic and tried to guess the color of the light from it, you would have no chance.

not sure i agree about "cars yield though".

i used to visit my former GF there and she said that the law in egypt used to be that if you injured a pedestrian in a car hit, you were responsible for them until they got better (and lots of fraud emerged as a result) but if you killed them, it was a small fine do drivers would actually back over you/speed up before hitting you to make sure you died.

not sure if that is one of those apocryphal stories or not.

the guys in cairo that amaze me are the flatbread delivery kids. they balance those 4X6 foot boards on their heads piled 2 feet high in bread, hold them with 1 hand and ride a bike through some of the most murderous traffic i have ever seen. it's cirque de soleil caliber stuff. they are really good riders (or have the life expectancy of a mayfly).

 
At 7/02/2012 4:23 PM, Blogger Hans said...

Excellent thread, Professor! I am planing to send this to our public semi-works department...

 
At 7/02/2012 4:23 PM, Blogger Methinks said...

I don't know about that rule, Morganovich. My family has never mentioned it. I think drivers pretty much try not to hit anyone, but I still hate crossing the street in the cities.

 
At 7/02/2012 4:29 PM, Blogger Methinks said...

Yes, but Ken, that fact doesn't support the growth of massive government bureaucracies that plant in the heads of simpletons the idea that we can't live without them.

That's interesting about distractions. My husband learned to drive in NYC and there are few road signs in the city. You mostly have to pay attention to what's happening in traffic, not signs. To this day, he is a menace anywhere outside the city. It's amazing. We don't let him drive.

 
At 7/02/2012 4:37 PM, Blogger Doug said...

True safe driving comes from realizing that lane lines and traffic lights are mere suggestions. The real information to keep your focus is the movement of the large objects on the roads, and knowing the potential threats from lack of visibility. Keep a constant spatial awareness of all the other cars and maximize visibility (panoramic rearview mirrors are great for this).

Stop lights extend commute times, which keeps more cars on the road for longer, increasing traffic, extending commute time. Roundabouts and no-traffic-light intersections are great.

 
At 7/02/2012 5:31 PM, Blogger Methinks said...

But, Doug, all that congestion gets everyone riled up about expanding old roads and building new ones. That creates JOBS, man!

What would a modern state be without make-work projects run by bloated bureaucracies directed by a bloviating political class? And if you dare criticize any part of that, the drones and useful idiots will point to the alternative - which is obviously Somalia.

You don't want to be mugged by pirates do you? What? What do you call"bloated bureaucracies and bloviating politicians"? Touche!

 
At 7/02/2012 5:57 PM, Blogger rjs said...

that's what happens in a civilized country...

if it were cleveland at rush hour, everyone'd be parked bumper to bumper under the light, cussing at each other while yacking about it on their cell phones...

 
At 7/02/2012 6:04 PM, Blogger Unknown said...

I scanned the comments and couldn't see my problem with the video as anecdotal evidence or its plural, data. When there's a power outtage I don't need a study or a video to understand that there'll be less vehicals on the road.

 
At 7/02/2012 6:37 PM, Blogger Noyes said...

There seems to be a similar amount of cars on the street below in both shots. You could be right though, one data point isn't conclusive...but it sure is compelling.

 
At 7/02/2012 11:03 PM, Blogger mongander said...

Something's missing in the video. The bottleneck is after the cars get through the light. Cars seem to be piling up in a right turn lane. Could the 2 videos be at different times of the day?

 
At 7/02/2012 11:05 PM, Blogger Methinks said...

Right, unknown, that's why if you scanned the comments carefully, you'd notice I brought up Egypt. Of course, you probably already know that blog comments are also not really the place where careful scientific analysis is conducted.

 
At 7/02/2012 11:26 PM, Blogger JakeW said...

This comment has been removed by the author.

 
At 7/03/2012 7:37 AM, Blogger Ken said...

Methinks,

I highly recommend the book to which I linked. I think you'd like it.

 
At 7/03/2012 8:28 AM, Blogger morganovich said...

methinks-

a question:

where in egypt are you talking about?

cairo has some of the worst traffic jams i have seen outside of mexico city and china. you get jams on the ring road at midnight. of course, some of this has to do with the fact that people drive donkey carts on the highway, but i i certainly would not put cairo on my list of cities with good traffic. it makes LA look like boisie.

 
At 7/03/2012 9:52 PM, Blogger VangelV said...

Be interesting to know statistics about accident rates comparing controlled and uncontrolled intersections with similar traffic flows.

I think that some of the data from the UK showed that accidents went down when lights were removed. Mark may have posted on this before because I recall seeing a video on the subject a while ago.

 
At 7/04/2012 10:58 AM, Blogger Methinks said...

Morganovich,

I didn't say that Cairo is a city with "good traffic". I said Egypt functions wilth almost no traffic signage or traffic lights. It takes a year to crawl anywhere in a car. These are overcrowded city problems.

My family is spread out across Egypt, so I've driven all over the place. There's even less signage in some of the smaller towns tourists never see and yet, drivers aren't incapable of avoiding crashing into each other (or the donkey carts - more common outside cities) in the absence of traffic lights.

 
At 7/04/2012 11:00 AM, Blogger Methinks said...

Ken, I'll check it out. Thanks.

 
At 7/04/2012 11:42 AM, Blogger VangelV said...

I didn't say that Cairo is a city with "good traffic". I said Egypt functions wilth almost no traffic signage or traffic lights. It takes a year to crawl anywhere in a car. These are overcrowded city problems.

I found the Cairo traffic to be a manageable nightmare. It was not the lack of signs that bothered me as much as the extreme speed of some cars that looked as if they were ready to fall apart at any moment.

 
At 7/05/2012 12:37 PM, Blogger Hydra said...

This wouldn't mean much without comparable traffic counts. If the power outage was general, many people would have stayed home from work to deal with domestic problems: finding and hooking up a generator, moving refrigerated goods to another location, dealing with pets, etc.

That said, studies have shown the premise to be true. Driving in Rome is hair raising, but Rome intersections apparently handle more throughput than the otherwise similar but overregulated American ones.

 
At 7/05/2012 12:43 PM, Blogger Hydra said...

Being raised on an island with no traffic lights, I would always yield to the person on the right. Even after I moved away and had to deal with traffic lights it took some time to break the habit. If someone was approaching (their red light) at a good clip on my right, I was prone to stop, even if I had the green (ignoring the light as in Cairo).

Needless to say this would freak out the people behind me. Nevertheless, it is good practice not to pull out in front of someone travelling at speed, assuming they won't run the light.

 
At 7/05/2012 1:28 PM, Blogger Heide Braley said...

I have often wondered about this. After watching this little clip, I am more convinced that traffic lights slow down traffic! Nice post.

 
At 7/06/2012 3:30 PM, Blogger Its GSATT said...

"Be interesting to know statistics about accident rates comparing controlled and uncontrolled intersections with similar traffic flows."

In my Ethics of Engineering course we had a guest speaker that was on a committee responsible for the majority of "round-a-bout" intersections being constructed in michigan and around the country. He was very proud of how "safe" these intersections were. However having had several of these built around my hometown of westbloomfield, mi (which he was especially proud of, they are seriously 3 or 4 lanes wide) I was less enthused. I finally got out of him that accident rates greatly rose after the intersection was installed, however the amount of fatal accidents were nearly eliminated since there were no more left handers getting t-boned.

So there is a trade-off, more fender benders, but fewer serious accidents. It could be argued both ways. Needless to say we had a very interesting discussion of the ethics of round-a-bouts.

 
At 7/07/2012 12:01 AM, OpenID Sprewell said...

I linked to this fantastic video by Stossel in the comments here a year ago, with similar info about the benefits of ditching traffic lights. I think the real issue is having a culture that respects the benefits of orderly behavior. Look at the traffic in India, a free-for-all where the largest vehicles, the buses, do whatever they want and you realize that lights and speed limits don't change much. However, I bet they have a lot less accidents there than you'd expect, certainly at a lot less cost since they're not spending billions on all the signals and other signs, like we do here.

 

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