[What Is Due from a Man Who Works on Another’s Car on a Half-Share and It Overturns]

Answer — and Allah is the One who grants success: What appears to me—Allah granting success—is that in such matters the operative reference is the custom practiced among the people of the region. If the custom is that when the car breaks down the driver is obliged to tow it to a mechanic’s workshop or to the owner, then the man is obliged to tow it, for custom rules.
– As for repair costs, they vary with the nature of the damage.
Traditionally, one-third of the income is allocated to the car, one-third to the driver, and one-third to the owner; and what the car needs—repairs, fuel, oil—is taken from the portion allocated to it.
As for when the damage results from an overturning, there are scenarios:
First scenario: The overturning is due to poor driving by the driver—such as exceeding the traffic rules known among drivers for such a vehicle. In that case, the driver bears responsibility for what occurred due to that conduct.
Second scenario: The driver loads the car beyond what is customary for such a vehicle—such that other drivers, upon seeing the load, denounce it and deem it to endanger the car on the road it will travel with that load—and this loading was without the owner’s permission. In that case, the driver is responsible for whatever damage, defect, or overturning occurred due to that loading.
Third scenario: The overturning is due to a cause inherent in the car—such as the stabilizer bar breaking, the air chamber (air system) malfunctioning, or the like—leading to an overturn or collision. In such a case, the driver does not bear responsibility.
Fourth scenario: The overturning or collision is due neither to the driver nor to the car, but to an external factor—such as another car obstructing the road. The responsible party then is the owner of the obstructing car, if he was at fault in that obstruction according to traffic regulations.
– If the driver was at fault, not the owner of the obstructing car, then the driver is responsible for what occurred to both cars.
– If the car overturns and breaks down far from its owner, the towing cost is taken from the revenues for two reasons:
1- Established custom and usage.
2- By analogy to losses in a muḍārabah (profit-sharing partnership), which are covered from the profit.
- The driver must tow the car and is entitled to the towing expense from the revenues—provided the accident was not due to his fault. If the driver caused the accident, then he is responsible for both towing and repairs.
If the car is in a secure place where there is no fear for it, and the driver had no role in its damage other than driving, he is not obliged to tow it.
– If the owner and driver dispute about the cause of the overturning, the matter is ambiguous, there is no evidence, and there is nothing in the car indicating the cause—such as the tires being intact, the axle intact, and the air chamber intact—then in that case the owner’s word is accepted; otherwise, the driver’s word is accepted.
And Allah is the Guardian of guidance and success. All praise is due to Allah, Lord of the worlds. And may Allah bless our master Muhammad and his pure family.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2