CPMapTemplate measurement units on screen

I am wondering how I change the measurement units on screen in my CPMapTemplate. In my screenshot below the distance is in miles, but how can I change that to kilometers?

Does this need to come from my route data?

I am not seeing this anywhere in the CarPlay programming guide or in the documentation.

These units should match the ones set by your user on-device, under Settings → General → Language & Region. Generally the units are derived from the user's region and locale.

CPMapTemplate measurement units on screen
 
 
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