Mike B

Hasn't Braess's Paradox been covered here before?


Did they discover this before or after NYC started closing roads to vehicular traffic?


The paper only makes the point that if *all* motorists use real-time maps to optimize their routes then the total throughput to decrease. This is unlikely to ever occur in practice and is easily prevented (limit accessibility of real-time data to some fraction of all drivers).

Just as with the study of law-breaking drivers summarized at , there is likely an optimal percentage of real-time-optimizing drivers that is greater than zero and less than one hundred. My OTA estimate is that the number who do use real-time routing is much much less than the optimal number; I thus find the mischaracterization of this study ("using real-time routing hurts traffic flow") counterproductive.


what happens if you take this to an extreme and close all the roads except one?

Robot Mistake

I thought that the problem in these studies is a poor definition of real-time systems.

The system changes faster then we can recieve updates when drivers are allowed to use the information to make decisions.

Oh. And yes. I have always believed that traffic would move faster if no one was allowed to changelanes (TM).


Interesting read, though after driving in Boston a couple of years, I'm convinced there is nothing short of shooting every driver on sight can improve driving conditions here.


This study is a good example of the risks of empirical work. Choosing routes between Harvard Square and Boston Common to study driver behavior is akin to choosing an Inuit village to stidy children's winter play patterns. They have WAY more winter than the rest of the world and they come from a different culture than most of us. Same is true for Boston/Camridge travelers. Thay have WAY more congestion and arcane routes than most of the rest of us and they practice a very different set of driving behaviors. Check out a copy of How to Be a Boston Driver for details.

I'd like to see this replicated with a true destination and a tightly defined origin, say Dodger Stadium and season ticket holders who live between Manchester and Artesia Blvd. in the South Bay. On game day, they could represent the marginal entrants casuing congestion on alternate routes.

Eric M. Jones

@7 Doc is absolutely correct.

My first experience of so-called "driving" in Boston evoked rage and outrage regarding the behaviour of other so-called "drivers". I was amazed; coming from LA where drivers are extremely polite and occasionally armed. The movie "Death Race 2000" comes to mind.

Knowledgeable locals avoid the Boston area at all costs. The comic-tragic Big Dig (Now 22 BILLION dollars and still not finished) has by all accounts made the traffic worse. NYC traffic is infinitely better.


Is the issue choice, or actionable information that a specific route is better this minute, available to a number of drivers that will swamp the route? Send random disinformation into the system: have some proportion of "real time maps" be ringers.


How about focusing on driving instead of using "real-time" driving maps while actually driving the car?


Really the solution should be to link the systems to properly distribute traffic.


As a lifelong Boston resident, I can confidently say that the Big Dig certainly improved the flow of traffic into, out of, and around the city of Boston. (Took long enough to get it that way.) Those who say otherwise do not remember the old roads. Considering the amount of cars now on the road, it is laughable to think that the old way was better. Not to mention that the North End can now see the sunshine...

Luigi Cappel

A true real time traffic solution using real time flow data should be able to continue to provide information as the flow changes.

There was a UK study proving that in many cases it doesn't matter what lane of a freeway you are in because the constant changing by many drivers evens everything out. I've experienced that many times in rush hour, watching my position against easy to recognise vehicles.

Real time traffic is much better than traditional systems where signs tell people to us 'the other route' which often leaves the existing route free of traffic. Maybe it's a conspiracy lol.


To all the Boston residents who still consider driving a nightmare, I would urge you to try commuting by bike. Not only is it fun and healthy, but it can also beat driving or taking the T most of the time, especially during rush hour, when riding a bike to get somewhere is usually much, much faster than being stuck in traffic.