Oh, that's because it has reached the target score. It will be one of the highest scorers for that generation and will be a parent of the next.

hm how annoying that is tho, wish there was a sandbox option to see how long it would run for

I'm enjoying the voting option, sort of like husbandry where you can see the traits you like retained more often.

I'm still stuck on one section (407 on my track) that is extremely vertical. I need to breed in some smaller wheels for the torque.

GF thinks I'm insaner(er).

I've been thinking the same thing, but it doesn't seem that smaller wheels give you much more. 45 degrees seems to be the limit even with 5 small wheels.
It's frustrating when the model is perfect, and shouting "ffs change down a gear!" doesn't help.

v2.2 has been released.

You can design your own cars, test them on various terrain, submit designs for testing etc. With the designer just make sure to assign colours to aid in component identification.