247SimpleTests
CDL · Driving Tank Vehicles

Why should you avoid hard braking when there are slick surfaces and a partial load in a tank?

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

Hard braking combined with surge on a slick surface can cause loss of control, fishtailing, or rollover

  1. A It does not matter on slick surfaces
  2. B Hard braking is illegal in every state
  3. C Hard braking combined with surge on a slick surface can cause loss of control, fishtailing, or rollover
  4. D Hard braking saves time

Why this is the answer

Slick surfaces reduce tire grip while surge adds an unpredictable forward force on the truck during braking. The combination is much more dangerous than either factor alone. Hard braking on a slick surface causes wheels to lock (or ABS to activate); locked or slipping wheels cannot resist the forward surge of the liquid; the trailer pushes the tractor sideways and the vehicle fishtails or jackknifes. On a slick surface with a partial tank load, brake very gently and very early, leave large following distances, and avoid hard maneuvering of any kind. If you must stop quickly, the calmest steady-pressure stop you can make is far safer than slamming the brakes.
Source: FMCSA CDL Manual 8.2.9 Slick Surfaces with Surge

Practice more questions

This question is from our CDL Practice Tests practice test. Take the full practice test to test your knowledge across all Driving Tank Vehicles and other topics.

Take the Tanker practice test →

About this topic: Driving Tank Vehicles

Driving a tank vehicle means managing a high centre of gravity and a shifting load: slow for curves well below the posted speed, brake early and smoothly, and never make sudden steering changes. These questions cover the handling rules for liquid loads. This is one of 21 Tanker questions on driving tank vehicles, each with a full explanation on a single study page.

New to this exam? Our CDL exam guide explains the format, scoring, and how to prepare.

Related questions

Driving Tank Vehicles

What is the most dangerous handling characteristic of a tank vehicle?

 Driving Tank Vehicles

How should you take curves in a tank vehicle?

 Driving Tank Vehicles

When stopping a tank vehicle, you should:

 Driving Tank Vehicles

What is 'fishtailing' in a tank truck context?

State-specific guides

Need information for your state? Our state guides cover local requirements, fees, and what to expect on exam day.

California Texas Florida New York Pennsylvania Illinois Ohio Georgia

Recommended study materials

Study guide

CDL Study Guide (Trivium)

Complete prep for all CDL written tests: general knowledge, air brakes, combination vehicles, hazmat, and all endorsements. Includes full-length practice tests.

Check Price → Study guide

CDL Practice Tests & Flashcards (Accepted Inc.)

600+ practice questions covering every FMCSA knowledge area, plus 400 flashcards for endorsement prep.

Check Price → Study guide

Master the CDL Truck Driver's License (Arco)

Arco's classic CDL prep with in-depth FMCSA manual coverage, endorsement chapters, and scored practice exams.

Check Price →

As an Amazon Associate, CJ Affiliate, and AWIN publisher we earn from qualifying purchases. Links above are affiliate links. Full disclosure →