A Personal Note: Hacking Traffic Lights

This is a brief followup to my previous post “A Personal Note: Mysterious Accident”

UPDATE: August 24, 2017

There are some known cases of hacking/tampering with traffic lights.

According to the Los Angeles Times, in 2009, two Los Angeles traffic engineers pleaded guilty to hacking into the city’s signal system and slowing traffic at key intersections as part of a labor protest in 2006.

According to the San Francisco Chronicle, in June 2005, police in Sunnyvale, California (where my accident occurred) requested assistance from the public to find a suspected sophisticated “trickster” who had been tampering with traffic lights for several months.

END UPDATE: August 24, 2017

It is possible to hack traffic lights and there has been some published research into how to do it for some traffic light systems.  Here are some links to articles and videos on the subject, mostly from 2014:





Talk by Cesar Cerrudo at DEFCON 22 on Hacking Traffic Lights

Someone with sufficient physical access to the traffic lights could always modify the hardware even if a computer-style “hack” was impossible.

I was driving a 1995 Nissan 200SX SE-R with minimal built-in electronics by modern car standards.  It would be difficult to hack my car without physical access and it was either with me, in a brightly lit parking lot at my office, or in a secured parking garage at my apartment building.

Just to be clear I am not saying my accident was caused by hacking of the traffic lights, only that it is possible.  As noted in my previous post, there are other possible explanations: an accidental failure of the traffic lights or a remarkable mental lapse on my part.  None of the three explanations seems likely to me.

(C) 2017 John F. McGowan, Ph.D.

About the author

John F. McGowan, Ph.D. solves problems using mathematics and mathematical software, including developing gesture recognition for touch devices, video compression and speech recognition technologies. He has extensive experience developing software in C, C++, MATLAB, Python, Visual Basic and many other programming languages. He has been a Visiting Scholar at HP Labs developing computer vision algorithms and software for mobile devices. He has worked as a contractor at NASA Ames Research Center involved in the research and development of image and video processing algorithms and technology. He has published articles on the origin and evolution of life, the exploration of Mars (anticipating the discovery of methane on Mars), and cheap access to space. He has a Ph.D. in physics from the University of Illinois at Urbana-Champaign and a B.S. in physics from the California Institute of Technology (Caltech).