Final answer:
A driver's brakes may be affected by Oil, Grease, or Brake fluid. These substances can reduce friction and hydraulic pressure, causing weakened braking. Road oil mixed with light rain reduces traction, while heavy rain can wash some oil away but still poses a hydroplaning risk.
Step-by-step explanation:
A driver's brakes may be adversely affected if they have any of the following substances on them: Oil, Grease, or Brake fluid. The presence of any of these substances can compromise the brake system's ability to perform effectively. When oil or grease contaminates the brake pads or discs, it can create a layer that reduces friction, making it harder to stop the vehicle. Similarly, brake fluid, if not contained within the system, can lead to a reduction in hydraulic pressure, also diminishing the braking power.
Regarding the control of the car during wet conditions, oil and gasoline leaks on the road surface can create a slippery film, especially when mixed with a light rain. The water mixes with oil and reduces traction, which can cause the car to skid or hydroplane, significantly reducing control. A heavy rain can sometimes help by washing away some of the oil, but it also can contribute to slippery conditions and standing water, which can also affect control and increase the risk of hydroplaning.