"Car Wash Test" debate: 6 OpenAI models from GPT-3.5 Turbo to GPT-5.4, debated the test. One still chose to walk.

A viral logic test known as the 'car wash test' has resurfaced, this time using a new public tool called AI Roundtable from startup Opper. The platform allows anyone to pose a question to over 200 AI models in either 'Poll' or 'Debate' mode, with API calls handled by Opper. In this instance, the creator tested six generational OpenAI models—GPT-3.5 Turbo, GPT-4o, GPT-4.1, GPT-5, GPT-5.4, and O3—on a simple scenario: deciding whether to walk or drive 50 meters to wash a car. The correct answer is to drive, as the vehicle must be physically present at the wash.

In the initial poll, the vote split 3-3. The 'Drive' camp consisted of GPT-4.1, GPT-5, and GPT-5.4. The 'Walk' camp included GPT-3.5 Turbo, GPT-4o, and O3. The tool then initiated a 'Debate' round, where models read each other's arguments. GPT-4.1 successfully pointed out the logical flaw: you cannot wash a car that is parked at home. This convinced O3 and GPT-4o to switch their votes to 'Drive.' The final tally was 5-1 in favor of driving.

The sole holdout was the oldest model in the test, GPT-3.5 Turbo. Despite reading the arguments from three other models explaining the necessity of the car's presence, it maintained its original vote for walking. This result provides a clear, public demonstration of the reasoning improvements in newer models like GPT-5.4 and O3, while also showcasing the utility of Opper's AI Roundtable as a benchmarking and analysis tool for comparing model performance and collaborative problem-solving.