Hmm, downloaded, generally very nice.
I think you really need to make two separate 'times of day' for it though.
If this is intended to be a night track then it's important to get the balance of values right.
Ie, right now the sky is very 'bright' for night time use, clouds 0.1 gets the klux value about right, but even then that is for a moon lit night...
The values for klux for the ambient also seem a bit high really.
Obviously these are easy tweaks to get right but when balancing all these things it's hard to get one right when others are wrong, so the glowing light stuff might need re-tweaking once other stuff has been tweaked, and since so much is dependent on the TOD then it's better to make the track a static and specific time of day, especially when going for a certain 'look' for the course too
Right away you could tell that illumination levels for the sky/ambient were too high, light reflections in a black car just didn't jump out.
Putting klux to ~ 0.001 for the sky, and ambient values to around 0.075 rgb suddenly made everything 'feel' much more natural. So just look up some real values for things to get them even in the right ball park and it'll start to come together much quicker in getting the look right
I can see a lot of potential for the course though, I'm excited to see where it's gonna go
Part of me thinks it'd look great with a full-moon evening, but a bit foggy too, so you get the close ambience of the light glows and don't need to worry too much about distance details (horizon), but benefit from some subtle shadows from the moon.
This is where per-track custom racer.ini values would be nice. With a lower resolution shadow map blurred a bit more the moon shadows would add a nice soft extra bit of depth to the course
Cheers
Dave