"Lead dogs" steer the rest of the team and set the pace. Leaders may be single or double; the latter is more common now, though single leaders used to be more common during the mid-20th century. Sometimes a leader may be unhitched (a loose or free leader) to find the trail for the rest of the team, but the practice is uncommon and is not allowed at races. Qualities for a good lead dog are intelligence, initiative, common sense, and the ability to find a trail in bad conditions.