Final answer:
Roadways are most slippery after it has been raining for a while and when it first starts raining. On a dry, summer day, roadways are less likely to be slippery compared to when it is raining.
Step-by-step explanation:
The slipperiness of roadways is influenced by various factors, including weather conditions. In general, roadways are most slippery after it has been raining for a while (option B) and when it first starts raining (option D).
During a heavy downpour (option A), the rain can wash away some of the oil and gasoline residue on the road surface, which can temporarily improve traction and reduce slipperiness. However, once accumulated water builds up, it can create a hydroplaning effect, making it more dangerous to drive.
On a dry, summer day (option C), the road surface is less likely to be slippery compared to when it is raining. However, it's important to note that roadways can still become slippery under certain conditions such as dust, oil leaks, or spills from other vehicles.