Doubles/Triples · Pulling Double/Triple Trailers
The federal required-knowledge list for the double/triple trailers endorsement names specific handling and stability characteristics an applicant must understand. Which set does 49 CFR 383.115(c) actually name?
1.Off-tracking, response to steering, sensory feedback, braking, oscillatory sway, rollover in steady turns, and yaw stability in steady turnsCorrect answer
2.Engine braking, transmission gearing, differential lock operation, tire load ratings, and axle weight distribution across the combination
3.Cargo securement methods, weight distribution across axles, and bridge formula compliance for the whole combination
4.Hours-of-service limits, logbook procedures, and roadside inspection levels for combination vehicles entirely, by rule
Explanation
49 CFR 383.115(c) names off-tracking, response to steering, sensory feedback, braking, oscillatory sway, rollover in steady turns, and yaw stability in steady turns. Unlike most of the required-knowledge paragraphs in Subpart G, this one is an unusually specific enumeration, so the list itself is the fact being tested here rather than a bare topic heading. The remaining options fail for the same reason: each names a real area of commercial driving, but none of them appears in 383.115(c), and each belongs to a different body of regulation entirely (equipment and drivetrain specifications, cargo and weight rules, and hours-of-service and enforcement rules).
Source: 49 CFR 383.115(c)
Related Pulling Double/Triple Trailers questions
- 49 CFR 383.115(d) requires a double/triple endorsement applicant to understand the problems a longer combination creates for other motorists in traffic. Which of these does that paragraph name?
- You are making up a set of doubles with one heavily loaded semitrailer and one light one. To handle as safely as possible once underway, where should the heavier trailer go?
- The crack-the-whip effect makes doubles and triples roll over more easily than a single-trailer rig. Which trailer in the combination carries the most risk, and what should the driver do about it?
- You are pulling a set of triples and approach a curve with a posted advisory speed you have driven comfortably many times in a tractor-semitrailer. How should you treat that speed?