DKTKey points on following distance for the South Australia learner test. Each answer is checked against the official South Australia handbook or road rules; use the practice-question links to test yourself.
In heavy rain, how should your gap behind the vehicle ahead compare with a dry day?
Answer: Bigger, because it takes longer to stop on a wet road
Wet roads lengthen stopping distance, so you need a larger gap behind the vehicle in front.
Practice question 372 · official source
How can you use a roadside post or sign to check your following gap?
Answer: Count the seconds from when the car ahead passes it until you pass it
Pick a fixed object, note when the car ahead passes it, then count how many seconds pass before you reach it.
Practice question 373 · official source
In wet weather or at night, how should you change your following gap?
Answer: Increase it to more than 3 seconds
Three seconds is the minimum; allow more when the road is wet or slippery, visibility is poor or it is dark.
Practice question 374 · official source
How do you check you have a 3 second gap?
Answer: Count 3 seconds after the car ahead passes a fixed object
Pick a fixed object, count three seconds after the vehicle ahead passes it, and you should reach it after you finish counting.
Practice question 375 · official source
Why should you avoid cutting in front of a truck or bus?
Answer: Trucks and buses need much more distance to stop
Heavy vehicles cannot stop quickly. Give them room, and do not pull in front of them as lights change.
Practice question 376 · official source
What minimum following distance does the SA Driver's Handbook call reasonably safe in good conditions?
Answer: The distance you travel in three seconds
Allow at least three seconds behind the vehicle ahead, and more when the road is wet or slippery or visibility is poor.