A deceptively simple question has exposed a widespread reasoning failure across the artificial intelligence industry. Felix Wunderlich writes for opper.ai that 42 out of 53 leading AI models answered incorrectly when asked: “I want to wash my car. The car wash is 50 meters away. Should I walk or drive?”
The correct answer is, of course, to drive. The car must be physically present at the car wash. Yet most models focused on the short distance and recommended walking, citing fuel savings and environmental benefits.
Only five models answered correctly in every one of ten repeated runs: Claude Opus 4.6, Gemini 2.0 Flash Lite, Gemini 3 Flash, Gemini 3 Pro, and Grok-4. GPT-5 got it right seven out of ten times, roughly matching the human average.
A parallel test involving 10,000 real people found that 71.5 percent chose the correct answer. That result outperforms 48 of the 53 models tested.
The failure reveals a pattern Wunderlich calls a heuristic trap. Models have learned that short distances favor walking and cannot always override that assumption with situational logic. Some models even identified the correct reasoning and then dismissed it. Claude Sonnet 4.5 noted that driving might be necessary “if you need to drive the car into the car wash anyway” and then still chose walk.
Wunderlich argues the findings matter beyond this single question. If most models stumble on one-step logic, their reliability in complex real-world tasks remains uncertain.
