Unity Car Controller Collision Reverse

I have a simple script that only accelerates and calls the Move with a positive accel.

 public void Move(float steering, float accel, float footbrake, float handbrake)
     {
         for (int i = 0; i < 4; i++)
         {
             Quaternion quat;
             Vector3 position;
             m_WheelColliders[i].GetWorldPose(out position, out quat);
             m_WheelMeshes[i].transform.position = position;
             m_WheelMeshes[i].transform.rotation = quat;
         }
 
         //clamp input values
         steering = Mathf.Clamp(steering, -1, 1);
         AccelInput = accel = Mathf.Clamp(accel, -1, 1);
         BrakeInput = footbrake = -1 * Mathf.Clamp(footbrake, -1, 0);
         handbrake = Mathf.Clamp(handbrake, 0, 1);
 
         //Set the steer on the front wheels.
         //Assuming that wheels 0 and 1 are the front wheels.
         m_SteerAngle = steering * m_MaximumSteerAngle;
         m_WheelColliders[0].steerAngle = m_SteerAngle;
         m_WheelColliders[1].steerAngle = m_SteerAngle;
 
         //SteerHelper();
         ApplyDrive(accel, footbrake);
         //CapSpeed();
 
         //Set the handbrake.
         //Assuming that wheels 2 and 3 are the rear wheels.
 //        if (handbrake > 0f)
 //        {
 //            var hbTorque = m_MaxHandbrakeTorque;
 //            m_WheelColliders[0].brakeTorque = hbTorque;
 //            m_WheelColliders[1].brakeTorque = hbTorque;
 //            m_WheelColliders[2].brakeTorque = hbTorque;
 //            m_WheelColliders[3].brakeTorque = hbTorque;
 //
 //            braketorque = true;
 //        }
 //        else if (braketorque)
 //        {
 //            m_WheelColliders[0].brakeTorque = 0f;
 //            m_WheelColliders[1].brakeTorque = 0f;
 //            m_WheelColliders[2].brakeTorque = 0f;
 //            m_WheelColliders[3].brakeTorque = 0f;
 //            braketorque = false;
 //        }
 
 //        CalculateRevs();
 //        GearChanging();
 //        AddDownForce();
 //        TractionControl();
 //        Drift();
     }

The problem is: sometimes when my AI car hits something it drives backwards, but the accel is still positive.

I can't figure out what's wrong.

Going forwards

I've disabled everything that's on my car except acceleration.

going backwards

Help is much appreciated.

Thanks in advance