Unity mobile car controller plus some low poly models.
You can use this template and modify it to suit your need to make your own game.
In Unity Editor you can also control the car by using WAD and left ctrl buttons on your keyboard.
Watch the demo here:
I’ve updated the project, so it has better car engine audio, has simple mini map (still in progress, I will update again with complete version of mini map), and it also have horn button; as seen in this video: