In fiction, road signs mean exactly what they say.
If the speed limit sign says 250, you had better be going 250. If a yellow caution sign warns of an impenetrable snarl of an intersection, a 360-degree vertical loop, or a moose, guess what you're about to see?
Further, any law-enforcement along the road will measure your performance according to the road signs (no matter how ludicrous, and even if they've been recently vandalized) and praise or punish you accordingly.
In a rare version, people who are either Genre Savvy or extremely horror-movie tier violent will disregard or kill the Too Dumb to Live people who are enforcing idiotically vandalised signs. Often leads to jokes regarding the "Slow Children Playing" sign.
- The cover of a paperback collection of B.C. strips famously featured a "Dip in Road" sign.◊ Sure enough...
- One The Far Side cartoon had a woman looking at a road sign and warning her driver about "cattle dancing." This activity is depicted on the sign and apparent on the road directly in front of the car.
- In one Belvedere strip a nearby sign says "Quiet: Hospital Zone." Belvedere, who's chasing a car, holds up a sign that says "Arf arf arf."
- Conchy: When Oom Paul finds himself hemmed in by a No Loitering sign, a One Way sign, and a No Entry sign, he looks annoyed and then flaps his arms and flies off.
- One of the Cannonball Run films showed a racer sticking numbers to a speed limit sign, changing it from 55 mph to 155 mph. They were driving a Lamborghini. So yeah...
- National Lampoon's When Nature Calls has, in succession, "Bear Left" (with a bear on the sign's left), "Bear Right" (same thing but reversed), and "Bare Breasts" (Exactly What It Says on the Tin).
- Pee-wee's Big Adventure has a series of signs of upcoming curves, each increasingly twisty and ridiculous. Followed by falling rocks. This scene is noted for Special Effects Failure, as you can see the signs moving along a track toward the camera.
- Invoked in the short story "Absolute Limits" by Guy Stewart, in which frustrated government scientists note that everyone on the highway always breaks the speed limit—so they have the speed limit on that stretch set to the speed of light.
- Red Dwarf has some fun with these. Rimmer quizzes Kryten on these while trying to get him certified for piloting a shuttle. Keep in mind this is taking place a few months shy of three million years away from Earth..
- The 'Tank Crossing' sign below was shown once in an episode of Home Improvement. For some reason, it was on the tank's road and not the cart path it crossed.
- Weaponizing this is one of the main powers of Kamen Rider Mach in Kamen Rider Drive. His main equippable upgrades are all based on road signs, and usually give his weapon, the Zenrin Shooter, different effects based on said road signs. For instance, if he uses the power based on a stop sign, he can paralyze enemies with his shots.
- In the video for the Gorillaz song "19/2000":
- The band passes a sign that reads "Loop Exit" just before entering a 360-degree vertical loop in the road.
- They also come upon a sign in the road depicting an irate moose. You shouldn't be surprised when the camera pans up to show a moose, but you might be surprised that it's hundreds of feet tall.
- The Muppet Movie has a map that says that there's a fork in the road. Sure, the road branches into two, but there's also a GIANT fork in the road! (which is apparently a real landmark)
Kermit: Hey Fozzie, I want you to turn left if you come to a fork in the road.
Fozzie: Yessir, turn left at the fork in the road... Kermit!
[they literally turn at a giant fork in the road]
Kermit: I don't believe it.
- The superhero parody game Stuperpowers includes this as a power a player can have: being able to make anything written on a road sign physically happen.
- In Gokujou Parodius (Ultimate Parodius), the highway-esque stage features plenty of yellow caution signs, mostly to indicate how the enemies are going to move. At one point, there is a caution sign for falling rocks, followed by falling rocks. Then there is a caution sign for moose, followed by falling moose. Then there is a caution sign with an exclamation point, followed by falling exclamation points...
- Subverted in the Sam & Max episodes. They remark the "One way" sign outside their office is the "least obeyed street sign in the country".
- The next-to-final dungeon in Persona 4 has "Shadow Crossing" signs strewn all over it, and you had better believe there are a ton of them.
- The second level of Air Buster plays this straight with signs warning the players of bends, narrows and splits in the high-speed tunnels.
- There she is!! has a No Cat and Bunny romance road sign. This is enforced by prejudicial cats and bunnies all over the city.
- This collection of humourous signs.
- Pyramid Head frequents this street.◊
- Cracked's 32 Alternate Interpretations of Common Warning Signs.
- SCP Foundation: SCP-1047 is a collection of anomalous road signs that if placed in a room indoors with a suitable concentration of carbon dioxide will forcibly apply effects based on their type to anyone in the room.
- In the obligatory Wacky Races-styled episode of The Wuzzles, one of Crock's myriad (backfiring) attempts to cheat involves doctoring an ordinary "Speed Limit 55 MPH" sign to read "Speed Limit 155 MPH" to get Rhinokey arrested for speeding. Rhinokey sees the sign and dutifully obeys it, but when Crock and his goons try to follow, traffic cop Eagle Beagle gives them a ticket for driving too slow.
- SpongeBob SquarePants once featured a characteristically bizarre version in which the signs announced "giant clams", "cheese graters" and — horror of horrors — "EDUCATIONAL TELEVISION".
- In Wacky Races, many of the times Dick Dastardly Stops to Cheat, it involves him flipping a directional sign so the arrow points in the other direction. Or he yanks a real road sign out of the ground so the others will miss the turn, or changes a 35 mph speed limit sign to read 85 mph. This one is oft-imitated in other cartoons where there's Wacky Racing.
- In the opening credits of I Am Weasel, Weasel's driving a convertible with a hot blonde. But he passes a road sign that reads "LOGO". He leaps out of the car in the direction the sign indicates and jumps into the logo for the show.
- This was a favorite gag of Tex Avery. If a character passed a "Fork ahead" sign, he would then bump into a giant fork sticking out of the ground. A "Hairpin turn" sign would indicate that the road would look exactly like a hairpin. And when characters stop at a school crossing, what should cross the road but a schoolhouse on two legs.
- Looney Tunes: Wile E. Coyote would frequently attempt to utilize these in his pursuit of the Road Runner. Unfortunately for him, Road Runners can't read.
- One of the Freaky Stories shorts involves an incredibly picky police officer, who expects everyone to follow traffic laws EXACTLY. Naturally, once he acquires a Speed Gun, he begins pulling people over for even going 1 Km/h faster/slower than the posted speed limit.
- Rocko's Modern Life parodied this with "Cheese Crossing" and "Slow Children Playing" signs. Also parodied with a PSA training video starring a clown.
- Dennis the Menace (UK): Dennis and his gang attempt to drive a line-marking machine which goes haywire and leaves white lines everywhere on the road. Cars naturally attempt to follow the line and end up driving on the footpath, through the park, etc.
- Garfield and Friends: Garfield and Odie walk up to a crosswalk, and Garfield stops Odie. He points up to the "Don't Walk" sign posted on the signpost and tells Odie he must always obey the signs. Then the sign changes to "Bark". Garfield is confused, but Odie obeys until it displays "Don't Bark". Then it displays "Polka". The two then dance across the crosswalk, with Garfield commenting that he doesn't understand it, but at least he's not getting a ticket.
- In one episode of Muppet Babies, Fozzie has an Imagine Spot about being in a city of chickens. At a crosswalk, the stop sign changes from "Don't Walk" to "Cluck", and all the chickens start squawking. Fozzie just says "Oh, well" and joins in.
- This is used as an occasional Running Gag in Grizzy and the Lemmings. Whenever both parties are chasing each other on a road with a runaway object and are about to fall off a cliff, there is a good chance of there being a warning sign near the bend that depicts the runaway object in question. No matter how specific it is.