The aircraft was carrying out a survey in a remote area. When last light occurred the aircraft was still some distance from the base camp. The pilot decided to follow a road into the camp. Enroute the engine lost power and an autorotational decent was carried out for a landing on the road. During the landing the left skid struck a low dirt bank and the tail rotor struck the dirt bank on the opposite of the road. Throughout the survey the pilot had used a higher than normal cruise power setting, but had not recalculated the endurance for the higher fuel usage. The engine failed after the fuel became exhausted.