Under normal driving conditions, the Alabama manual recommends a following interval of at least:
Correct answer: C. – Two seconds
Use the two-second rule by selecting a fixed roadside object and counting after the vehicle ahead passes it. If you reach the object before finishing the two-second count, increase your distance. Poor road or weather conditions and longer vehicles call for a larger interval of four or five seconds.
Source: Alabama Driver Manual — Ch. 4, “How to Avoid Rear End Collisions”


