Question about actions and AddReward

Hi
I have a karting game and my agent receives a vector assigned to acceleration

```

public override void OnActionReceived(float[] vectorAction)
{ acceleration = vectorAction[1];


}
```

when training I can see that 50% of the time acceleration is less than 0 and 50% of the time it is more than 0, which is to be expected, the result is my kart jiggles a bit but doesn't move forward

in order to make the kart move forward I added a reward when the acceleration is positive and a penalty when it is negative

```

public override void OnActionReceived(float[] vectorAction)
{ acceleration = vectorAction[1];

if(acceleration > 0)
{
AddReward(1f);
}
else if(acceleration < 0)
{
AddReward(-1f);
}
}
```

I would expect to see over time the ratio would be in favor of more positive acceleration numbers being produced, however the ratio is still 50/50

Am I fundamentally misunderstanding something here?