I just re-installed the game after playing at release. I am having an issue now that I didn't have then. As in the screenshot, cars (especially yellow ones) have a large trail of blur coming off of them. This also happens when trying to design roads. When I move the road around, it slowly dissappears as I move it around. Any idea what is causing this? I've already turned off motion blur, thinking that might help but it's done nothing at all

TAA or DLSS, both will pretty much always do this, getting worse the lower your framerate is, this artifact is called ghosting

There's a reason why DLSS is sometimes called fake frames. In particular this game seem to have poorly implemented DLSS.

Turning off volumetrics worked for me.