From my research, it appears that using distance based functions for the spline component like
Get Location at Distance Along Splineresult in precision issues.
A lot of video game stuff is smoke & mirrors + good-enough approximation, sure. I’ve never ever experienced anything like this with splines, though. Might be wrong but I’d blame the movement method / something else than sheer lack of precision. Not at this scale and scope.
Could you replicate it with a single car and / or explain the movement method?