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Green Lights Are Sometimes The Worst Thing That Can Happen

April 23, 2013

Suppose a computer virus wanted to take over the traffic signals in Los Angeles. What’s the worst that could happen?

The scenario is not as far fetched as you might think. Los Angeles announced last month that they have now synchronized all 4500 of their traffic signals all across the city. The first major city in the world to do so.

Conceivably, a computer virus could be written to attack the software that controls the lights. If the system was compromised, what is the worst that could happen?

I just finished reading Daniel Suarez’s excellent novel “Daemon.”
It’s about a computer program that gains sentience and plots to take over the world. As a technologist, I enjoyed it because Suarez gets the computer stuff correct. Of course, he has to invent some technology that doesn’t exist yet, like sentient computer daemons. But, overall it’s a frightening look at one possible future as we continue to automate our systems. Suarez’s daemon uses much of our existing technology against the humans who are trying to contain it.

I finished the book about the same time I noticed the LA traffic light story.

So, what’s the worst that could happen?

You might think that the worst thing the computer virus could do would be to turn all the lights to red, or maybe simply turn them off entirely.

But, the more I thought about it, the more I realized that rather than turn the lights all red, the worst thing the virus could do is turn them all green instead. If the light is red, we all stop. Eventually, we’d figure out it’s not turning green for anyone and we’d treat it like a 4-way stop sign. The city would grind to a halt.

On the other hand, if the lights all turned green, we’d speed through an intersection and get t-boned by someone coming the other way. Every intersection would become a pile of twisted wrecks.

Because I’m a manager, I immediately thought of LA’s traffic lights as a metaphor for our projects. One of the recent positions I worked at, our portfolio, or department had about 40 active projects at any one time. We were constantly spinning up new projects, finishing existing projects and evaluating the burn rate of current projects. If you announced a freeze on all our projects (turn the lights to red) we’d have a whole lot of folks sitting around with nothing to do. But, we’d be able to reevaluate and restart projects as needed. We would blow our schedules, but we would not blow our budgets. On the other hand, if you came into our portfolio and green lighted every project on the board, we’d quickly run out of money, and we would run out of resources. We’d have a whole bunch of collisions as projects that should be done in sequence were all of a sudden started in parallel.

Our company had a very conservative leadership structure. It was a non-profit and the members of the board were not technologists. One of them came and spoke to the IT department one time.

“We understand that you want to push the technology forward. Please understand that we are forcing a slower pace on purpose. As an organization we have to be more conservative than you would like.”

So, the next time you are frustrated by upper management delaying a project, think of LA. The worst thing that could happen would not be turning all the lights red. The worst thing would be to turn them all green.

Edit: My wife’s niece is married to a Civil Engineer who specializes in traffic systems. He assures me that it is possible to programmatically set all the lights to red, but the traffic symbols are hard coded in such a way that it’s impossible to programmatically set them all to green. It would require a manual override at each traffic signal. I’m now less worried about driving in LA. (Thanks, Sarah!)

  1. Sarah permalink

    Actually, all the lights being turned green is impossible. The signal boxes are hardwired to go to all red if something should happen. If someone or something would care to have all green light intersections, they would have to go to every single control box and change them manually. Just saying.

    • That’s good to know, I suppose. LOL. We won’t all die in a horrible crash from a rogue computer virus.


      • John permalink

        That what fail safes are for, so that a failure mode is a safe mode. As explained by Jamie from Mythbusters. After a radio controlled car took out several sections of fence when it got out range and would not engage the brakes. It was immediately reset so that the brakes engaged as soon as the car got out of range of the controller.

      • My nephew is a traffic engineer and he assures me that the fails are position is all red. To get them all green you’d have to manually change each one.

        Of course he told me this AFTER I wrote this article.

        But we are probably safe from traffic hackers in that respect.

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