I am classed as partially colour blind.  I can't differentiate with much accuracy between green and brown primarily.

 

So to the subject at hand... The sat nav in my car shows the "route" in a colour i find difficult to see. Is there an way to change the "route" colour settings?

 

 

i used a garmin sat nav in old car and the route showed up as a nice, easy to see blue  lines

 

No

Try forcing it in to night mode to see if that helps otherwise you are stuck with the colours.

Could you use Apple CarPlay (or the Android equivalent) and your phone's navigation system instead?

I have the same problem. Disappointed with the colour scheme, I will try night mode as it looks better for me.