Final answer:
In rainy weather, mandatory stops are crucial due to the increase in slipperiness from oil and gasoline on the road, which can lead to loss of vehicle control and accidents.
Step-by-step explanation:
The reason for the mandatory stop in rainy weather is due to the presence of oil and gasoline on the road surface. When a light rain falls, it can cause these substances to rise to the top, making the surface more slippery and difficult to control the car. A heavy rain may wash away some of the oil and gasoline, reducing the slipperiness, but the increased water on the road can lead to hydroplaning where the tires lose contact with the road surface entirely. This condition severely impacts the control of the vehicle, increasing the likelihood of accidents.
In summary, a mandatory stop in rainy weather helps to ensure safety by accounting for the greater stopping distances required under compromised road conditions. Additionally, adhering to traffic signals, like those at tollbooth stations which may employ a piece of wire to alert the station of an approaching car, minimizes the potential for accidents that are more common in wet conditions.