The only setting that made a difference for me on the suggested line is the world colorblind filter, tritanopia. The problem is that it makes everything change, including car paint color, and not just the one thing I have a problem with.
The suggested racing line is the most difficult thing for me to see because of its rapidly changing colors for gas/coast/brake. Please isolate that setting.
Couldnt agree more. Im deutan colourblind and im the same - the tritan world filter is the only way i can see the racing line 
its a cool feature but it ruins every other colour. Making a racing line-specific colourblind filter would immensely help us.
Additionally, if they feel like it would fit the art style, they could add a 3D racing line (like in the f1 games).
I think the best way would be to let us pick 3 colours for the racing line arrows
I agree 100%! I turned it on for the racing line and then all the red cars were pink… Stupid. I only need it because the bright colored racing line’s green and red look the same. All I really need is a higher contrast on the racing line. Everything else can stay the same.
I was just looking for a setting for this and then found this thread after googling it. Glad I’m not the only one! The game looks beautiful and the colors are all great, except I can’t see the racing line
Yes I struggle to see the braking indicator often thanks to blinding effects by the environment. The colors get washed out alot sometimes almost vanishing. Now you add a cockpit cam with a shallow angle and it is even more difficult to see.
The colors should be isolated more from lighting effects, all 3 colors should be free to choose. And additional modes should be availible, like 3D, maybe solid lines like GranTurismo.
Its not much we are asking for a supposed flagship title.
F1’s done this for a few years, it’s a good addition.
Please, please let users adjust the contrast and colours for driving lines, which also includes braking lines too. I really struggle with this and don’t want have to change the world colour options, just to make a UI setting easier to see.
As others have suggested, having the option to set the three colours separately and also being able to change the contrast of the lines would be incredibly useful for those of us that struggle with the colours as they appear on different types of road surface / lighting and weather conditions, etc.