The Counterintuitive Science of Traffic Jams

Tom Vanderbilt, author of Traffic, gave a 23-minute talk on the counterintuitive science of congestion at the Boing Boing: Ingenuity conference in San Francisco last month. Turns out a lot of the problems we ascribe to poor roads or other drivers are really our own fault. You can watch the video below:


Brad Plumer, at Washington Post, summarizes the talk:

— Self-driving cars steered by robots could do a lot to reduce traffic jams.That’s because the human inability to maintain a steady, constant speed on the road is responsible for a lot of congestion. Japanese physicists discovered this when they had people try to drive around in steady speeds on a circular road. Jams materialized out of nowhere. People braked erratically and started responding uncertainly to people ahead of them.

— Cars tend to drive closer to bicyclists who are wearing helmets. That comes from Ian Walker, who set up a bicycle with sensors and drove around the city. Vehicles tend to crowd closer to him when he was wearing a helmet than when he wasn’t. That’s not necessarily surprising, but it’s a reminder of all the weird unconscious tics we adopt while driving and making on-the-fly assumptions.

— There are all sorts of fun patterns in who honks their car horns. In what sounds like a exciting job, researchers sat at intersections and refused to move when the light turned green to see who honked at them. Men honk more quickly than women. People with expensive cars also honk more rapidly — although people in convertibles are less likely to honk.

— There are also fun patterns on driver courtesy. Older drivers are more likely to stop for others. Drivers are more likely to be courteous when the other car has extra passengers inside. People also are more likely to violate traffic rules the closer they are to home — a “familiarity effect.”

—  There are all sorts of optical illusions that can trick human drivers. Fog makes objects seem like they’re moving slower than they really are. And experiments show that humans are really bad at judging the speed of an oncoming train at a crossing until it’s nearly arrived. Another point in favor of self-driving cars, perhaps.

—  Congestion often looks tantalizingly easy to clear up — in theory. One study that tracked drivers in Boston during rush hour found that if you could remove just 1 percent of people on the road (say, to mass transit), you could achieve a whopping 18 percent improvement in traffic flow. But  for whatever reason, cities haven’t figured out how to do that just yet.

I can’t wait for self-driving cars.

Los Angeles Synchronizes Traffic Lights

The New York Times reports the city of Los Angeles has synchronized all 4,500 traffic lights:

Now, in the latest ambitious and costly assault on gridlock, Los Angeles has synchronized every one of its 4,500 traffic signals across 469 square miles — the first major metropolis in the world to do so, officials said — raising the almost fantastical prospect, in theory, of driving Western Avenue from the Hollywood Hills to the San Pedro waterfront without stopping once.

Will the move reduce the number of accidents in the city?

Is Sitting in Traffic Killing You?

A troubling piece in the Wall Street Journal, “The Hidden Toll of Traffic Jams,” explains the deleterious effects of sitting in traffic jams:

New public-health studies and laboratory experiments suggest that, at every stage of life, traffic fumes exact a measurable toll on mental capacity, intelligence and emotional stability.


Recent studies show that breathing street-level fumes for just 30 minutes can intensify electrical activity in brain regions responsible for behavior, personality and decision-making, changes that are suggestive of stress, scientists in the Netherlands recently discovered. Breathing normal city air with high levels of traffic exhaust for 90 days can change the way that genes turn on or off among the elderly; it can also leave a molecular mark on the genome of a newborn for life, separate research teams at Columbia University and Harvard University reported this year.

The evidence is still largely circumstantial, as the article notes, but it is worrisome. My daily commute is about twenty miles one way, and I sit in traffic for close to two hours daily. That’s one aspect of my life that I would like to change.

The Upside of the Blackberry Outage

After the three-day Blackberry outage across Europe, Africa, and the Middle East, The National (the English newspaper of the United Arab Emirates) reports the upside of the said outage:

A dramatic fall in traffic accidents this week has been directly linked to the three-day disruption in BlackBerry services.

In Dubai, traffic accidents fell 20 per cent from average rates on the days BlackBerry users were unable to use its messaging service. In Abu Dhabi, the number of accidents this week fell 40 per cent and there were no fatal accidents.

I’d like to see more concrete evidence here, but anecdotally, this makes sense: texting kills.

One statistic from the article that seems excessive to me:

On average there is a traffic accident every three minutes in Dubai, while in Abu Dhabi there is a fatal accident every two days.

Does anyone know of such traffic statistics for other cities around the world?

On Living in Atlanta

Atlanta has been my home for most of my life. It’s a massive, sprawling city unlike any I’ve lived or visited in the world.

In the latest issue of More Intelligent Life, a correspondent for The Economist, Jon Fasman, reminisces about living in Atlanta, after having lived in New York City, Washington D.C., Hong Kong, London, and Moscow (Russia). It’s a great read.

Ah, the big ice storm in February of this year which shut the city down:

The weekend after we moved down, it snowed. Not much—an inch or two over a full day—but it shut the city down. Something similar but worse happened this year: a three-inch storm coupled with a week of below-freezing temperatures shut the city down for nearly a week.

I like this comparison:

Different cities are suited to different seasons: a few years back I was posted to Moscow, which blooms in the winter and wilts in summer. New York’s summer days are repulsive—walking outside feels like swimming through garbage soup—but there is no place I’d rather spend a summer evening. Atlanta is built for spring and fall—the pleasant seasons, and Atlanta is a profoundly pleasant city. 

Vivid descriptions in this paragraph. Though I suspect you can extend the relaxation into the weekends in Atlanta (at least, in my view, more so than you would in New York City):

That is not as easy as it seems. New York is thrilling, Hong Kong a marvel of density, Moscow the closest a city can get to a cocaine level of jitteriness and excitement, London endless: I love all four places, but I would never describe them as pleasant. They are none of them as comfortable and human-scaled as Atlanta. Social life just sort of happens here. In New York and London my calendar filled up weeks in advance; here it is not unusual to look forward to a relaxing, empty weekend on Thursday and then find that Saturday and Sunday are frantic.

Lastly, I have to agree with the author’s assessment here. Atlanta has terrible traffic (I believe Atlantans spend more time in traffic getting to their jobs than anywhere else in the country), our public transportation system (MARTA) is severely limited, and schools ITP aren’t on the same level as those OTP.

 Atlantans divide the area into “ITP” and “OTP”—Inside the Perimeter and Outside the Perimeter, the highway that rings the city and its closest suburbs. Most of the area’s population is O; most of its charms are decidedly I. One quirk of Atlanta’s development is that urban areas like mine feel rather rustic, while suburbs that were rural 30 years ago are now strip-malled, parking-lotted and planned-communitied into blacktopped uniformity. For all its charms, Atlanta provides an object lesson for mid-sized cities today in how not to grow. It sprawls, it really does have bad traffic, and thanks to a befuddling stew of overlapping city and county governments, it has negligible public transport and dysfunctional state schools. Better to treat the perimeter as a national border, and cross it only on trips abroad.

Do read the whole article and don’t miss the solid recommendations on what to do/see at the bottom of the piece.

If you’re a native to Atlanta, what’s your opinion on the author’s take of Atlanta? If you’ve only visited Atlanta, how does it differ from other cities you’ve visited?