Question Roadways are the most slippery: Answers During a heavy downpour. After it has been raining for awhile. During the first rain after a dry spell. Explanation Many roads are most slippery during the first rain after a dry spell because oil and dust on the road have not previously been washed away. Pass your DMV Written Test with flying colors Take me to the cheat sheet California This questions appears in the following tests: California Practice Test 5 California Practice Test 12