What is "Pro Speed"?
OVERDRIVE and OVERDRIVE: Fast&Furious Edition include a "Pro Speed" option that allows you to change the top speed. Read more about this feature in this article.
By default, your app will have "Pro Speed" activated which means that your cars will be able to reach the highest-possible top speed that the combination of support items, game mode and Commander level allows.
If you feel that you'd prefer a lower top speed, you can simply deactivate this option by going to the Settings Menu and unticking "Pro Speed":