When following a large vehicle, what minimum safe distance is generally recommended?

• A. Two seconds
• B. Four seconds or more, depending on conditions
• C. Eight seconds
• D. One second

Answer: (B)

The key idea is giving yourself enough time to notice, react, and stop if the vehicle in front slows suddenly. Large vehicles require more space because they have longer stopping distances and bigger blind spots, so the safe rule is to keep four seconds or more of following time. In normal conditions this four-second buffer is enough, but you should add extra space when roads are wet, icy, slick, or visibility is poor, or when following a heavy load or cresting hills—five to six seconds (or more) may be needed in those cases. A practical way to measure it is to pick a fixed object on the road; when the lead vehicle passes it, start counting seconds. If you reach that object with your vehicle in less than four seconds, back off a bit.

The other options don’t fit because one or two seconds is too little for a heavy vehicle, and eight seconds is more than needed in typical driving. One second is clearly unsafe.