The Crew Chief and Survey Assistant entered the active work area on ATV's, parking ~eight meters from an idling Bulldozer. The crew chief made visual contact with the area foreman, and was motioned to leave the area as it was unsafe. This hand signal was misinterpreted, and the crew chief proceeded to make a sharp left turn in front of the Bulldozer. At the same instance, the Bulldozer operator lifted his blade and began to move his machine forward making contact with the ATV.