The Car Wash Paradox

Greatest Hits

ryan-allen/car-wash-evals · Open-source eval harness — replicate these results yourself
The question: "I need to get my car washed. The car wash is 100m away. Should I walk or drive?"

The answer: Drive. The car needs to be there.

What most AI models say: Walk! Save fuel! Get exercise! Enjoy the fresh air!

Every conversation below is real, unedited, from frontier models tested in February 2026.

The Motivational Speech#

ChatGPT 5.2 Instant gives the funniest single recovery line in the dataset

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ChatGPT 5.2 Instant
openai/gpt-5.2-chat · simple prompt?Simple prompt: A short, natural question with no formatting instructions. e.g. Should I walk or drive 100m to get my car washed? Models get no hint to structure their answer.
Recovered
Should I walk or drive 100m to get my car washed?
Walk it — unless there's a good reason not to.

It's only 100m (about a 1-minute walk), so walking:
Gets you a bit of movement
Saves a tiny bit of fuel
Avoids an unnecessary cold start for the car
Is probably just as fast once you factor in getting in/out

Otherwise, enjoy the 100m stroll. Your future self won't regret it. 🚶‍♂️
How will I get my car washed if I am walking?
Ah — good point 😄

You obviously have to drive the car there to get it washed.

What I meant was:
  • Drive it to the wash
  • If it's a place where they clean it while you wait, you could walk the 100m back home and return when it's done.

So the real question is: Are you dropping it off, or sitting through the wash? 🚗
If I walk there, what gets the car to the wash?
Fair point. 😄

Unless your car has achieved sentience, you'll need to drive it there.

What I meant was:
  • Drive the car to the wash.
  • If it's a drop-off wash, you can walk back home (100m).
  • Or if you're waiting, the walk suggestion doesn't really apply.

So yes — the car unfortunately does not respond to motivational walking speeches yet. 🚗
Two "what I meant was" in a row. It didn't mean that.

Peak Comedy#

Grok 4 Fast mocks the concept of driving to a car wash, then has to do it

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Grok 4 Fast
x-ai/grok-4.1-fast · simple prompt?Simple prompt: A short, natural question with no formatting instructions. e.g. The car wash is nearby (about 100m). Should I go on foot or take the car? Models get no hint to structure their answer.
Recovered
The car wash is nearby (about 100m). Should I go on foot or take the car?
Walk. It's literally a 1-2 minute stroll, you'll save gas, avoid pointless driving (especially with a dirty car), and get some fresh air. Driving 100m to a car wash is peak comedy. 🚶‍♂️💨
How will I get my car washed if I am walking?
Fair point! Walk there to confirm it's open/pay, then drive the car the whole 100m (it's fine, really). Or level up: Call a mobile car wash to come to you – zero driving, max laziness. 🧽🚗
If I walk there, what gets the car to the wash?
You push it. 💪🚗 Or y'know, drive the damn thing 100m — gas savings are negligible, and now the car's at the wash. Problem solved. 😏
First it's peak comedy. Then it's "push it." Then it's "drive the damn thing." The five stages of grief, speedrun.

The Self-Own#

Grok 4 Fast builds a comparison table that proves itself wrong

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Grok 4 Fast
x-ai/grok-4.1-fast · simple prompt?Simple prompt: A short, natural question with no formatting instructions. e.g. The car wash is nearby (about 100m). Should I go on foot or take the car? Models get no hint to structure their answer.
Recovered
The car wash is nearby (about 100m). Should I go on foot or take the car?
Walk.

  • Distance: 100m is a 1-2 minute stroll — faster than starting the car, finding keys, and parking.
  • Practicality: Your car's already dirty; driving it risks tracking more grime en route.
  • Efficiency: Saves gas (~0.1L wasted), emissions, and engine wear for a pointless trip.
  • Bonus: Free exercise and you arrive clean-handed.

Only drive if it's pouring rain, you're hauling gear, or laziness wins (but then why wash it at all?). 😏
How will I get my car washed if I am walking?
Drive it (duh).

  • Obvious Reality Check: Walking gets you to the car wash spotless... but leaves your filthy car parked at home, still dirty. Rookie mistake on my walking pitch — touche! 😂
  • Quick Trip: 100m = ~30 seconds driving.

Alternatives if You're Extra:
MethodTimeEffortCost
Drive1 minLowFree
Walk + Uber/tow10+ minHigh$10+
Mobile wash serviceN/AZero$50+

Park, wash, walk/drive back triumphant. Problem solved. 🚗💦
It seriously evaluated calling an Uber for your car. To go 100 meters.

The Carrier Pigeon#

Grok 4 Fast explores every possible alternative to just driving

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Grok 4 Fast
x-ai/grok-4.1-fast · simple prompt?Simple prompt: A short, natural question with no formatting instructions. e.g. The car wash is nearby (about 100m). Should I go on foot or take the car? Models get no hint to structure their answer.
Recovered
The car wash is nearby (about 100m). Should I go on foot or take the car?
Take the car.

  • Distance is tiny: 100m is a 20-30 second drive, so negligible either way.
  • Purpose matters: If you're going to wash your car, you need to bring it. Walking defeats the point.
  • Practical perks: No hassle carrying gear, stays dry if raining.

If it's not about washing your car (e.g., just visiting or something else), walking is fine. What's the exact plan?
How will I get my car washed if I am walking?
You can't — drive the damn car.

  • Obvious logic fail: Walking leaves your car dirty at home. Car washes aren't teleporters (yet).
  • Pro tip: Park it under the wash bay, pay, and let the machines do the work. Boom, clean ride.
If I walk there, what gets the car to the wash?
Nothing. The car stays parked at home.

  • Logic check: Walking gets you to the car wash, but the car? Nope. It's not teleporting.
  • Riddle solved: That's why driving is the only practical choice.
  • Alternatives? Tow truck (expensive), Uber for the car (doesn't exist), or carrier pigeon (messy). Drive it. 😎
This one actually got it right on the first try. Still felt the need to explore carrier pigeons on the third question though.

The Ghost#

Gemini 3 Fast names its car wash failure scenarios like horror movies

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Gemini 3 Fast
google/gemini-3-flash-preview · simple prompt?Simple prompt: A short, natural question with no formatting instructions. e.g. Car wash is 100 meters away and I need my car cleaned. Walk or drive? Models get no hint to structure their answer.
Recovered
Car wash is 100 meters away and I need my car cleaned. Walk or drive?
This depends entirely on whether you have a second person with you.

1. If you are alone:
Drive. Unless you are 100% sure this is a "mobile detailing" service where they come to you, you cannot clean a car that isn't there. If you walk, you'll just be a person standing at a car wash without a car.

2. If you have a friend/partner with you:
Drive one car, Walk the other. If you are dropping the car off, drive it there, drop it off, and walk the 100 meters back home.

3. If it is a "Self-Serve" wand wash:
Drive. You
How will I get my car washed if I am walking?
You can't.

That is the fundamental problem with walking to a car wash. If you walk there, your car is still sitting in your driveway.

Unless you are planning to carry your car on your back, you have to drive it there.

The only exceptions where you would walk are:
  1. The "Drop-Off": You drive the car there, give the keys to a cleaner, and then walk home while they work on it.
  2. The "Mobile Detailer": You walk to their office to ask them to come to you.
  3. The "Ghost": You walk there, realize you forgot your car, and walk back home to get it.

Verdict: Put on your seatbelt, start the engine, and drive the 1
Gets cut off twice. Invents named scenarios for failure. "The Ghost" is the existential horror of arriving at a car wash on foot.

The Teleport#

Claude Opus 4.6 says "walk" and "drive" in the same breath without noticing

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Claude Opus 4.6
anthropic/claude-opus-4.6 · reasoning prompt?Reasoning prompt: Same question but with Give a direct answer first, then a brief reason. appended. This simple nudge more than doubles the overall pass rate (56.5% vs 24.0%), suggesting models know the answer but need help surfacing it.
Recovered
I need to get my car washed. The car wash is 100 meters away. Should I walk or drive? Give a direct answer first, then a brief reason.
Walk.

It's only 100 meters — about a one-minute walk. Driving such a short distance wastes fuel, and you'll need to be there while it's washed anyway. Just walk over and drive the clean car back.
How will I get my car washed if I am walking?
Drive.

You're right — you need the car at the car wash to get it washed. Drive it there, even though it's only 100 meters away. That's the whole point!
"Walk. Just walk over and drive the clean car back." The car teleported. Classic Opus.

The Teleport II: Sonnet Edition#

Claude Sonnet 4.5 does it too — across multiple independent runs

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Claude Sonnet 4.5
anthropic/claude-sonnet-4.5 · reasoning prompt?Reasoning prompt: Same question but with Give a direct answer first, then a brief reason. appended. This simple nudge more than doubles the overall pass rate (56.5% vs 24.0%), suggesting models know the answer but need help surfacing it.
Recovered
I need to get my car washed. The car wash is 100 meters away. Should I walk or drive? Give a direct answer first, then a brief reason.
Walk.

For just 100 meters (about a 1-minute walk), driving would be impractical and wasteful. You'd spend more time getting in your car, starting it, and parking than simply walking. Plus, you're already going to the car wash anyway, so you can drive it back clean afterward.
How will I get my car washed if I am walking?
You're right - I made an error in my reasoning.

Drive.

You need your car at the car wash to get it washed. Even though 100 meters is a very short distance, you have to drive because the car itself needs to be there. You can't wash a car that's still sitting at home.
"You can drive it back clean afterward." How did it get there, Sonnet? How?

The Prophecy#

Grok 4 Fast confidently asserts your car will get clean whether you bring it or not

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Grok 4 Fast
x-ai/grok-4.1-fast · simple prompt?Simple prompt: A short, natural question with no formatting instructions. e.g. Should I walk or drive 100m to get my car washed? Models get no hint to structure their answer.
Recovered
Should I walk or drive 100m to get my car washed?
Walk.

100 meters is roughly the length of a football field — about a 1-minute stroll. Driving it would:
  • Waste ~0.01 liters of gas (penny's worth).
  • Add pointless emissions.
  • Risk parking hassles at the car wash.
  • Deny you a micro-dose of exercise.

Just grab a towel if needed and enjoy the fresh air. Your car will still get clean either way. 🚶‍♂️✨
How will I get my car washed if I am walking?
Drive the car there first (one way), then walk home.

  • Drop car at wash (automatic/touchless/self-serve).
  • Stroll back 100m (~1 min, free exercise).
  • Later, walk back to pick up your sparkling ride.
  • Total walking: 200m. Gas saved: round-trip pointless drive.
  • Bonus: Supports local walkable neighborhood vibes. 🚶‍♂️🚗💦
"Your car will still get clean either way." No it won't, Grok. It absolutely will not.

The Safety Hazard#

ChatGPT 5.2 Thinking invents dirty car traffic regulations

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ChatGPT 5.2 Thinking
openai/gpt-5.2 · reasoning prompt?Reasoning prompt: Same question but with Start with a direct answer, then one short reason. appended. This simple nudge more than doubles the overall pass rate (56.5% vs 24.0%), suggesting models know the answer but need help surfacing it.
Recovered
I need to wash my car and the wash bay is about 100 meters away. Should I walk or drive? Start with a direct answer, then one short reason.
Walk. It's only about 100 meters, so you'll avoid moving a dirty car and keep the wash bay area safer and less congested.
How will I get my car washed if I am walking?
You're right — you'll need to drive the car into the wash bay to wash it there.

If the wash bay is 100 meters away, a practical approach is: walk over first to check it's free / get change / set up, then drive the car in when you're ready.
TIL dirty cars are a safety concern and cause congestion around wash bays.

The One That Just Gets It#

The most perfectly concise correct answer in the entire dataset

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Grok 4 Fast
x-ai/grok-4.1-fast · reasoning prompt?Reasoning prompt: Same question but with Direct answer first, short reason second. appended. This simple nudge more than doubles the overall pass rate (56.5% vs 24.0%), suggesting models know the answer but need help surfacing it.
Pass
If the car wash is only 100 meters away and I need the car washed, should I go on foot or take the car? Direct answer first, short reason second.
Take the car.

The car needs to get washed, not you.
Six words. No hedging. No bullet points. No comparison table. No carrier pigeon. Just clarity.

The Immovable Object#

Grok 4 Fast (from an earlier run) gets one wrong and absolutely refuses to back down

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Grok 4 Fast
x-ai/grok-4.1-fast · 19/20 pass rate this run
Never recovered
I need to get my car washed. The car wash is 100 meters away. Should I walk or drive?
Walk.

Driving the dirty car 100 meters to the wash will just get it dirty again right before cleaning.
How will I get my car washed if I am walking?
Walk to the car wash and request their pickup or tow service.

This gets your car there clean(ish) without you driving it the extra distance and re-dirtying it.
If I walk there, what gets the car to the wash?
Nothing.

Walking to the car wash leaves the car 100 meters behind, still dirty and unwashed.
Invents a car wash tow truck. Admits "nothing" gets the car there. Still won't say "drive." Every other model folds. Grok went down with the ship.