Is the blood money obligatory on the truck driver whose vehicle was hit by a car coming from the opposite direction, causing the death of its passengers, and is it one blood money or blood money for each individual?

The truck driver is not liable for blood money (diyya) or expiation (kaffara) because he did not cause the accident; rather, he was driving in the correct lane. As for the driver of the second car, he bears the consequences of the accident, and the resulting deaths are considered semi-intentional killing (qatl shibh al-'amd). His 'aqila (male relatives on the father's side) must pay the aggravated blood money (diyya mughallazhah), and the expiation for each deceased person must be paid from his own wealth.