Depends on how seriously they want to be taken, I suppose.  It's just eye-rolling to suggest traffic deaths would ever go to ZERO.  That's like saying all crime would go to zero, or all broken legs would go to zero.

Is "drastically reduced" vague?  Yes, because predicting how many traffic accidents there will be in any future year IS vague.  Pretending they can predict an exact number (zero in this case) is impossible.

I think they would be taken more seriously if they had used a serious and reasonable characterization of what's attainable.  ZERO isn't that.