> I had assumed that reasoning models should easily be able to answer this correctly.
I thought so too, yet Opus 4.6 with extended thinking (on claude.ai) gives me > Walk. At 50 meters you'd spend more time parking and maneuvering at the car wash than the walk itself takes. Drive the car over only if the wash requires the car to be there (like a drive-through wash), then walk home and back to pick it up.
which is still pretty bad.
And on the flip side, even without thinking, Gemini 3 flash preview got it right, with the nuance of the possibility of getting supplies from the place (which tbh I as a human first thought this was about when I opened this thread on HN).
> Since you are going to the car wash, the choice depends entirely on *how* you plan to wash the car:
### 1. Drive if: * *You are using a drive-through or self-service bay:* You obviously need the car there to wash it. * *You are dropping it off:* If you are leaving it for a professional detailing, you have to drive it there. * *The "50 meters" is on a busy road:* If you have to cross a major highway or there are no sidewalks, it’s safer to just drive the car over.
### 2. Walk if: * *You are just going to buy supplies:* If you have a bucket at home and just need to run over to buy soap or sponges to bring back to your driveway. * *You are checking the queue:* If you want to see if there is a long line before you commit to moving the car. * *You are meeting someone there:* If your car is already clean and you’re just meeting a friend who is washing theirs.
*The Verdict:* If you intend to get the car washed at that location, *drive.* Driving 50 meters is negligible for the engine, and it saves you a round trip of walking back to get the vehicle.