Which of the following best describes the road surface condition during the first 10-20 minutes of rainfall after a long dry period?

1. The road is cleanest because the initial rain washes away all debris.
2. The road is safest as the water provides extra tire cooling.
3. The road is extremely slippery due to a mixture of water, oil, and dust.
4. The road has the most grip because the water fills in cracks and potholes.