Someone who is 'impartial' is objective, unbiased and who treats all equally. If you are impartial you are not personally or emotionally involved in something and therefore better able to view a situation and make a fair assessment.

1. As someone unconnected to either side in the dispute, I was in a position to offer an impartial opinion on who was at fault.
2. Even though his fans were convinced that he won the fight, most impartial observers agreed that a draw was the fair result. 
3. The fact that the judge in the case personally knew the defendant led many to question his impartiality. In the interest of fairness, another judge was eventually chosen.  

1. We regularly use focus groups in order to get an impartial view of our products.
2. We are taking steps to ensure our hiring process is impartial and unbiased.