You are driving a 60-foot tractor-trailer at 55 mph. The minimum following distance you should maintain is:
Correct. Above 40 mph, add one extra second to the per-10-foot rule. A 60-foot vehicle = 6 seconds + 1 = 7 seconds at 55 mph.
CDL Practice Question #11
Category: General Knowledge
Why this question matters
This question is one of 97 in our General Knowledge bank. The reasoning above comes directly from the AAMVA CDL Manual, the source document used by every U.S. state DMV. Memorizing the underlying rule — not just the letter answer — is what separates passing on the first attempt from a return trip and another fee.