Self-driving? How about self-washing?

Toyota Motor Corp. thinks cars that can drive themselves should be able to clean themselves, too.

The automaker filed a U.S. patent application for a system that would allow autonomous vehicles to sense when they’re dirty and drive to a car wash. The system determines when the vehicle has traveled on an unpaved road or in bad weather and how long it’s been since the last wash.

If the vehicle decides it needs a wash, it then calculates whether it has enough time to get one before the next time it needs to be somewhere. The application notes that the system would be useful for vehicles used in car-sharing services.

It also says such a system could be used with nonautonomous vehicles, though instead of getting a wash itself, the car would notify the driver via a dashboard light or smartphone alert that it’s time to get one.