Texas Driver's License Knowledge TestSafe Driving PracticesMedium
A driver is traveling at 60 mph on a highway. Under ideal dry conditions, what is the minimum safe following distance in car lengths, assuming one car length per 10 mph?
- A7 car lengths
- B4 car lengths
- C6 car lengths
- D5 car lengths
Show answer & explanationAnswer & explanation
Correct answer: C. 6 car lengths
A common rule of thumb for following distance, especially taught for new drivers, is to allow one car length for every 10 mph of speed. At 60 mph, this equates to 6 car lengths (60 mph / 10 mph per car length = 6 car lengths).
Why the other options are wrong
- A. 7 car lengths would be for 70 mph; while safer, it's not the minimum calculation for 60 mph.
- B. 4 car lengths would be appropriate for 40 mph, not 60 mph.
- D. 5 car lengths would be appropriate for 50 mph, not 60 mph.
Following Distance (Car Lengths)
A general guideline for safe following distance is to allow one car length for every 10 miles per hour of speed.
- Provides adequate reaction and braking time.
- Increases with speed and adverse conditions.
- Easier to visualize than time-based rules for some drivers.
Memory trick: Every ten, add a car; in bad weather, add more afar.