A passenger bus collided head-on with a fuel tanker truck on a highway on Indonesia's Sumatra island on Wednesday, killing at least 16 people and injuring four others, officials said. The crash occurred around midday on the Trans-Sumatra Highway in North Musi Rawas regency of South Sumatra province, when an intercity bus carrying at least 20 people struck a tanker truck traveling in the opposite direction, said Mugono, a local disaster management agency official. Mugono, who uses a single name like many Indonesians, said preliminary findings indicate the bus — which was traveling from South Sumatra's Lubuklinggau city to Jambi, another city — may have emitted sparks shortly before the collision. This may have prompted the driver to steer the vehicle toward the right side of the road in an attempt to avoid a more serious incident. However, an oil tanker truck was approaching at high speed, leaving little time to avoid a direct impact.…