Lighting glitch

From what I could gather, it appears to be caused by the extreme roughness of the road materials' surface maps layered on top of the textures, which are creating these these shaded pockets of noise everywhere as the shallow angle of the car lights "hit" those overly strong craggy surfaces. I could be way wrong, but I do know something ain't right.

It should be easy enough for them to greatly reduce the intensity of that junk one way or another. Hopefully to the point where there's no black pixels at all, but I don't really see it happening since there's only a handful of people talking about this stuff, and they have a lot on their plates already with all the other issues still existing in this game. This is one of those things where i just do not understand how it shipped with the game. Did no one on the team or in QA drive any stages at night? The fact that everyone thought it was okay over there makes a fix or adjustment in the future seem far less likely to me. Truly baffling situation when you see it in action and then think about how and why it made the retail version of the game.

For now (and possibly forever with this one), I'd recommend keeping the headlights off and cranking the game's brightness up for the night stages. It's a silly workaround, and not realistic or immersive, but at least you can see to drive at night then without the extreme distraction of the road surface shimmering and flickering full of those black pixels in the headlights.

It seems the majority of people don't have any issues with it. Had a look at your thread and that exactly what I'm getting. wonder if its to do with specific hardware? what gpu are you running?

i find it odd that the light at the edge of the road is fine, make sense what you say regarding the angle of the light causing the issue.

Nvidia 3060 in that PC, so it's definitely not an AMD specific issue.

With the edges of the roads being fine as you say, I'd have to imagine it's entirely because they're different textures and resolutions with different normal/diffuse/roughness/etc maps that may or may not be set as strongly.

Blowing up a part of one of my screenshots:

You can see the curb / gutter along the edge doesn't appear to have the same kind of noise and black pixels like the road surface does, it looks like a regular basic texture. I wish the roads themselves were more like that. They probably don't have surface maps like the roads do, or if they do it's not cranked up as high as it is on the roads.

Is that what you mean by edge of the road?

Because the ground/grass/terrain to the right of the curb does have the extra roughness. However, those textures appear to be a lower resolution than the roads. So while the surface mapping there may be cranked just as high, the shaded blackened crevices appear larger because of the lower resolution with less surface "detail" packed in. Still bad in a way, but also not as noisy in action compared to the actual roads, and also not as distracting since your eyes aren't focused on that like they are the actual roads up ahead. Perhaps arguably too strong, but makes more sense for dirt and grass that's not driven on constantly to be very rough an uneven and have those gaps.

If you go into photo mode during a night stage replay, you can get above the road surface and look straight down on it right next to the headlights, and all sorts of other angles to see this extra surface mapping detail, how unnecessarily strong it is, how it interacts with the bright headlights, and when it starts to really be visible and produce all the unwanted noise and shimmer and black pixels.

I wonder if reinstalling the game might help? 

Yeah, anything from the literal edge, ie in Greece the it's a small sharp bank, that always seems to be lit fine without glitches, I don't seem to have it as bad on the banks as your screenshot. 

Nah, a reinstall won't do anything for this.

They have to tweak the materials for the road textures themselves to reduce these results, and / or adjust the headlights to not do this sort of thing (if that's even possible).

I don't know what the best or easiest fix would be, but it's out of our hands unless maybe texture swap mods become possible in the future.

I know from making Session maps in UE4 it's really not hard to reduce the intensity of something like a normal map, it just may be a little time consuming to do that for every single road and surface texture/material that exists in this game. They gotta do something, though. It's bananas.

adding antialiasing isn't an acceptable fix since the TAA (at least currently) introduces blur and trails, I'll have a go of reducing Anisotropic filtering though.
also possibly relevant/related issue, lots of visual noise and glitches going on at night, driving the Hyundai i20 Rally1 in Chile:

Chile

I've downloaded and a reinstalled the game (1gb fibre so wasn't long to do) and it does seem to have helped the issue a lot, with the same or higher detail settings I can now do them without going cross eyed or feeling sick. So might be worth you trying?