nomnomdeplume

I think there are a lot of implicit assumptions in such a short prompt.

Is it a self-service car wash? If not, walking to the attendant and handing them your keys makes more sense.

If it is self-service without queuing, there may be no available spaces/the bay may not be open, requiring some awkward maneuvering.

If you change it to something like:

I want to wash my car. The unattended, self-service car wash is 50 meters away. All of the bays are clear and open. Should I walk or drive? Break each option down into steps, and estimate the amount of time each takes.

You're more likely to get correct responses.