I experimented a lot and found a 35 FPS lock to be the smoothest gameplay you can achieve with no stuttering. For most people who don’t have the highest end hardware, 35 fps brings the best combination of performance (smooth driving game play) while being able to keep the graphics options high. While 30 FPS isn’t bad, most people who have framerate issues would benefit from running the game at 35-40 locked FPS.
The issue is that it only offers a 60 or 30 frames per second option (and lower.) A frame limiter is included in the game’s advanced settings, as you presumably already know, and it works nicely. If you purchased Sleeping Dogs on PC and are experiencing stuttering or low FPS while driving, there is a fantastic patch available.