Which following statement is true about following distances and speed for a bus on dry roads with good visibility?

Which following statement is true about following distances and speed for a bus on dry roads with good visibility?

• A. A 30 mph speed requires 5 seconds of space
• B. A 50 mph speed requires 4 seconds of space
• C. A 30 mph speed requires 4 seconds of space
• D. A 50 mph speed requires 6 seconds of space

Answer: (C)

The key idea is using a safety buffer measured in seconds to account for a bus’s slower acceleration and longer stopping distance. On dry roads with good visibility, a four-second following distance is the practical minimum for a large vehicle like a bus at moderate speeds. This interval provides enough time to perceive a slowdown, react, and begin braking before you reach the vehicle ahead. As speed increases, stopping distance grows more quickly, so you’d need more than four seconds at higher speeds to maintain a safe margin. That’s why a six-second gap is more appropriate at around 50 mph, while four seconds at 30 mph keeps you safely spaced without being overly cautious. So, the statement that a bus at 30 mph requires four seconds of space matches the common guideline for safe following distance in this scenario. The other options either overstate the needed space at the lower speed or underestimate the space required at the higher speed.

The key idea is using a safety buffer measured in seconds to account for a bus’s slower acceleration and longer stopping distance. On dry roads with good visibility, a four-second following distance is the practical minimum for a large vehicle like a bus at moderate speeds. This interval provides enough time to perceive a slowdown, react, and begin braking before you reach the vehicle ahead.

As speed increases, stopping distance grows more quickly, so you’d need more than four seconds at higher speeds to maintain a safe margin. That’s why a six-second gap is more appropriate at around 50 mph, while four seconds at 30 mph keeps you safely spaced without being overly cautious.

So, the statement that a bus at 30 mph requires four seconds of space matches the common guideline for safe following distance in this scenario. The other options either overstate the needed space at the lower speed or underestimate the space required at the higher speed.