To maintain a safe following distance behind the vehicle ahead, which rule is recommended at speeds over 30 mph?

To maintain a safe following distance behind the vehicle ahead, which rule is recommended at speeds over 30 mph?

• A. the one-second rule
• B. the three-second rule
• C. the four-second rule
• D. the two-second rule

Answer: (C)

At speeds over 30 mph, you need more space to react and stop safely, so using a four-second following distance is recommended. The idea is simple: pick a fixed point ahead on the road, like a sign or a marked line. When the car in front passes that point, start counting seconds: one thousand one, one thousand two, one thousand three, one thousand four. If you reach the same fixed point before you finish the count, you’re too close and should ease back to create more space. Why this works: as speed increases, your stopping distance grows because it takes longer to perceive a hazard, react, and brake. The four-second rule gives you enough time to respond to sudden slows or stops by the vehicle ahead, reducing the chance of a rear-end collision. In poor conditions—rain, snow, or slick pavement—give even more space beyond four seconds. So the four-second rule is the safe standard at higher speeds, whereas shorter counts (one-, two-, or three-second rules) don’t provide enough margin for reaction and braking.

At speeds over 30 mph, you need more space to react and stop safely, so using a four-second following distance is recommended. The idea is simple: pick a fixed point ahead on the road, like a sign or a marked line. When the car in front passes that point, start counting seconds: one thousand one, one thousand two, one thousand three, one thousand four. If you reach the same fixed point before you finish the count, you’re too close and should ease back to create more space.

Why this works: as speed increases, your stopping distance grows because it takes longer to perceive a hazard, react, and brake. The four-second rule gives you enough time to respond to sudden slows or stops by the vehicle ahead, reducing the chance of a rear-end collision. In poor conditions—rain, snow, or slick pavement—give even more space beyond four seconds.

So the four-second rule is the safe standard at higher speeds, whereas shorter counts (one-, two-, or three-second rules) don’t provide enough margin for reaction and braking.