Which of the following is NOT a common cause of fires in commercial vehicles?

Answer: A — Fuel leaks

Fuel leaks can be a significant fire hazard in commercial vehicles, as fuel is highly flammable and can easily ignite when exposed to heat or sparks. It's crucial for drivers and operators to regularly inspect their vehicles for any signs of fuel leakage to mitigate this risk. Overheated tires pose a serious threat as well, as they can burst or ignite due to excessive heat generated from driving at high speeds or overloading the vehicle. This can lead to a sudden loss of control and potential fire. Faulty electrical systems are another common cause of fires. Defective wiring, short circuits, or overloaded circuits can create sparks or excessive heat, which may lead to ignition. High cargo weight, while it can lead to other issues such as increased braking distance and reduced handling, does not directly contribute to fires in the same manner as the other options. It is not typically recognized as a common fire hazard in commercial vehicles, making it the correct choice as it does not share the same level of risk associated with starting a fire.