Thanks for your detailed comment!
The smoothnesss of the road seems to be a recurring comment from players, and we definitely agree that is is an issue. Sometimes, even despite the player’s efforts, the line is jagged and any little step stops the car on the spot, which is definitely not what we wanted.
We think that these little unwanted steps in our line drawing are the biggest issue, rather than the car’s suspension. The cars do have suspension by the way, but as you said it definitely needs some tuning.
We are working on a fix and will surely upload an update when the rating period is over :)