If it is raining and you are tired, you probably should not be driving - you are a hazard to yourself and other drivers when you drive in those conditions. However, if you must drive, keep a solid 10 to 15 seconds of following distance between you and the next car on the road.
It is five seconds
I usually leave 5 to 6 seconds minimum following distance under those condition, and have had no accidents . . .
If it is raining and you are tired, you probably should not be driving - you are a hazard to yourself and other drivers when you drive in those conditions. However, if you must drive, keep a solid 10 to 15 seconds of following distance between you and the next car on the road.
5
Low beams
When driving, when should you follow the four Rs
i guessed 8 seconds
20
10/15
You follow the vehicle ahead of you by 3 seconds, you should never plan a path where you will be unless you are switching lanes and need to know how much space you have because while driving things can change in an instant, for good defensive driving just be prepared for anything at any time, and always follow vehicles by 3 seconds from the time their rear bumper passes an object until your front bumper passes the same stationary object
3 seconds
10-15