There are many solutions to this.
One would be polynomial interpolation
Another solution that just got out of my head:
- move the camera towards the car every frame. the distance is e.g. 5 units + 5 * car speed. you could also move it a bit towards the back of the car.
- the camera always looks at a direction that is something between the looking line (e.g. positive Y-axis) and the direction the car's physics force is pointing.