The FPS can be anything. The FPS doesn't affect the speed of the cars - if you have low FPS (which means, a longer time between frames), the cars will move more between frames. If you have high FPS (which means, very short time between frames) the cars will move less between frames. But both ways, it will take the same number of seconds for a car to drive from A to B!
So if the cars look like they're too fast to you, it's because Colossal decided to make them go at that speed, not because there's anything wrong with your PC.
Ideally, FPS should be between 20fps and 60fps, I think. Lower than 20fps and your eyes can tell that you're looking at a fast slideshow rather than a moving thing. Higher than 60 doesn't make a difference, and you're probably wasting money buying hardware capable of doing more than 60fps. (I'm sure someone can contradict me here!)
(A very long time ago, like in the early 1990s, high FPS would mean that games could run too fast. Computers had buttons to slow the processor down for older games, like down from 66MHz to 10Mhz... That isn't necessary anymore, the games can work all that stuff out automatically.)
By the way, I generally get around 10fps, because my computer is old and below the minimum specs. The game doesn't look as pretty as the developers intended, but it's still completely playable and a lot of fun for me!