Traffic lights are extremely susceptible to being hacked in fiction. This can be done to show off a hacker's (or AI's) power, or for the more pragmatic reason of letting the hacker and his buddies make their escape via car while their pursuers are stuck in the resulting traffic jams. Bonus points if all the lights glow green (or any given colour), as opposed to, you know, the green ones.
Of course, in Real Life
Not Everything Is Online
— traffic lights aren't hooked into the Internet. This makes this a subtrope of Artistic License - Engineering
A more dangerous variant is hacking the signals that coordinate train movements, or the warning lights where train tracks and roads intersect.
Anime and Manga
- Fujimaru of Bloody Monday did this from his laptop to stop the terrorists from escaping with his kidnapped sister (Chapter 12).
- Done at the start of the You're Under Arrest! movie as part of a terrorist plot created by an ex-Tokyo Metropolitan Police officer in order to prove his work on how to cause a terror attack on a country with first world standards.
- The technopath Satsuki Yatoji from X1999 is introduced hacking a street light from her cellphone while riding a bicycle.
- Ghost in the Shell: Arise: "Ghost Whispers", the hacking of traffic system electronics including the lights are done by rogue JGSDF Ranger soldiers in order to prove that they are serious when they want their imprisoned CO freed of false charges.
Live Action Television
- In the furry sci-fi novel A Fox Tail Vulpie does this with his phone for fun the day before unleashing a viral AI on the world.
- Done near the end of "Marshall Pucci" in the 2010 version of Human Target.
- In the Agents Of Shield episode "Girl in the Flower Dress", Miles does this to get away from Coulson. It works, temporarily.
- In an MacGyver episode, Mac "hacks" the stoplights in a town in Europe to help him make his getaway, by putting fragments of a credit card in a timing gear.
- Lie to Me: the episode "Saved" has an interesting variation of this trope. Cal Lightman finds that a particularly heroic paramedic saves so many lives because she knows where the accidents will be. That's because her brother hacks into traffic lights and purposely causes deadly accidents.
- In The Blacklist, the kid pretending to be the feared hacker Ivan hacks the streetlamps in his hometown as part of an attempt to impress a girl.
- One episode of Intelligence has Gabriel use his chip to change the traffic lights to allow him and Riley to catch up to a suspect.
- Champions supplement C.L.O.W.N.. When the founding members of C.L.O.W.N. were just teenagers, one of their "pranks" was to cause all of the stoplights in town to turn green at the same time. The writer of the supplement apparently didn't realize that this would cause cars to crash into each other in the intersections, leading to mass injury and death.
- The d20 Modern supplement "Urban Arcana" includes a spell which changes red lights to green in the path of the player's vehicle.
- Watch_Dogs: Aiden Pearce is shown to be able to do this. In the E3 demo, he uses this ability to turn all of the lights of a busy intersection to green, causing a massive pileup that kills a few civilians.
- Mega Man Battle Network: in Colorman.EXE's scenario, he hacks into the traffic lights and causing them to flash many colors, confusing the traffic.
- Super Solvers: Midnight Rescue features a story about Morty Maxwell using his magic powers to mess around with the traffic lights so they were all the wrong colors and sprouted an umbrella, too.
- In Spiderman The Animated Series, the Hobgoblin gains access to the Kingpin's computer console, and raves about the information he'll be able to control. The first thing he does is create traffic chaos.
- In Count Duckula, there was one episode with an intelligent and slightly evil computer, who invites Duckula to play a game about traffic lights. It turns out it controls real traffic lights.
- In the The Penguins of Madagascar episode, "Go Fish", Kowalski hacks the city's traffic lights in order to stop a fish delivery truck so that the other penguins can steal fish from it. Unfortunately, he accidentally licks one of the wires when he thinks about fish, causing the light to turn green and the fish truck to get away.
- Teen Titans Go!, "Hey, Pizza!": Beast Boy and Cyborg do this on the tower mainframe in one of their attempts to slow down the pizza delivery man in hopes of getting free pizza. It doesn't work.