Study guide
3.4 Putting the Vehicle in Motion: Accelerating, Steering, and Stopping Smoothly
Commercial Driver's License CDL
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1 Chapter 1: CDL Overview, CLP, and Federal Licensing Regulations
1.1 CDL Classes, Endorsements, Restrictions, and Testing Architecture (49 CFR Part 383) 1.2 Entry-Level Driver Training (ELDT) and the Training Provider Registry (49 CFR Part 380) 1.3 Commercial Learner's Permit (CLP) Rules and Driver Disqualifications 1.4 Medical Self-Certification Categories, Other CDL Rules, and the International Registration Plan
2 Chapter 2: Vehicle Inspection and Maintenance
2.1 The Seven-Step Pre-Trip Inspection Method 2.2 Critical Safety Components: Steering, Suspension, Brakes, and Tires 2.3 En Route Inspections, Post-Trip DVIR, and Out-of-Service Criteria
3 Chapter 3: Basic Vehicle Control and Operating Fundamentals
3.1 Instrument Controls, Engine Starting, and Shutdown Procedures 3.2 Shifting Gears: Manual Transmissions, Double-Clutching, and Progressive Shifting 3.3 Backing Fundamentals, GOAL Principle, and Basic Maneuvering 3.4 Putting the Vehicle in Motion: Accelerating, Steering, and Stopping Smoothly
4 Chapter 4: Speed Management and Stopping Distances
4.1 The Three Components of Total Stopping Distance (Perception, Reaction, Braking) 4.2 Speed Management on Curves, Slippery Roads, and Downgrades 4.3 Hydroplaning, Speed vs. Weight, and Reduced Visibility Adjustments
5 Chapter 5: Space Management and Defensive Driving
5.1 Managing Following Distance and Space Ahead (The 1-Second per 10-Foot Rule) 5.2 Space Beside, Behind, and Overhead Clearance Management 5.3 Turning, Off-Tracking, and Managing Space in Intersections 5.4 Space Below and the Space Needed to Cross or Enter Traffic
6 Chapter 6: Visual Search, Hazard Perception, and Communication
6.1 Visual Search: Looking 12-15 Seconds Ahead and Mirror Monitoring (5-8 Seconds) 6.2 Identifying Hazards: Work Zones, Pedestrians, Distracted Drivers, and Slow Vehicles 6.3 Communicating Intent: Signaling, Flasher Use, Horn, and Breakdown Warning Triangles (49 CFR 392.22) 6.4 Distracted Driving and the Federal Mobile Phone and Texting Rules (49 CFR 392.80 and 392.82) 6.5 Aggressive Drivers and Road Rage: Recognition, Prevention, and Response
7 Chapter 7: Driving in Extreme and Adverse Conditions
7.1 Night Driving, Low-Beam/High-Beam Management, and Glare Recovery 7.2 Driving in Fog, Heavy Rain, Snow, and Severe Winter Conditions 7.3 Hot Weather Driving, Tire Blowout Prevention, and Radiator Overheating
8 Chapter 8: Emergency Maneuvers, Skid Control, and Accident Procedures
8.1 Evasive Steering, Off-Road Recovery, and Emergency Braking (Controlled vs. Stab) 8.2 Recognizing and Recovering from Drive-Wheel and Front-Wheel Skids 8.3 Post-Crash Procedures, Fires (Extinguisher Classes), and Emergency Incident Response
9 Chapter 9: Mountain Driving and Downgrade Techniques
9.1 Engine Braking, Auxiliary Retarders, and Gear Selection Before the Grade 9.2 Snub Braking Technique vs. Continuous Braking and Brake Fade 9.3 Runaway Truck Ramps and Emergency Descents
10 Chapter 10: Railroad-Highway Grade Crossings and Special Intersections
10.1 Railroad Crossing Procedures, Warning Systems, and Passive vs. Active Crossings 10.2 Mandatory Stop Requirements (Hazmat, Passenger, School Bus) and Clearance Safety 10.3 Low-Clearance and Low-Ground-Clearance Hanging Hazards at Crossings
11 Chapter 11: Cargo Securement and Weight Distribution
11.1 Federal Weight Limits (GVWR, GCWR, Axle Limits, Bridge Formula) and Center of Gravity 11.2 Cargo Securement Rules, Working Load Limits, Tiedowns, and Covering Requirements 11.3 Cargo Types: Liquids/Baffles, Dry Bulk, Over-Dimensional Loads, and Inspection Intervals (50 mi / 3 hr / 150 mi) 11.4 Blocking, Bracing, Header Boards, Covering Loads, and Sealed or Containerized Cargo
12 Chapter 12: Air Brake Systems Overview and Operation
12.1 Air Brake System Components: Compressor, Governor, Air Tanks, Safety Valves, and Drain Valves 12.2 Brake Chambers, S-Cam Mechanism, Slack Adjusters, and Spring Parking Brakes 12.3 Dual Air Brake Systems, Low Air Warning (60 psi), and Emergency Spring Brake Pop-Out (20-45 psi) 12.4 Air Brake Pre-Trip Inspection and Step-by-Step Leak Rate Testing 12.5 Antilock Braking Systems (ABS): Required Vehicles, Malfunction Lamps, and Braking With and Without ABS
13 Chapter 13: Combination Vehicles Overview and Coupling
13.1 Combination Vehicle Dynamics: Rollover Risk, Rearward Amplification, and Trailer Jackknifing 13.2 Coupling and Uncoupling Step-by-Step Procedures: Fifth Wheel, Kingpin, Air and Electrical Lines 13.3 Trailer Air Lines (Service vs. Emergency/Supply), Glad Hands, and Trailer Protection Valves 13.4 Inspecting Combination Vehicles: Walk-Around Additions and the Combination Vehicle Air Brake Check
14 Chapter 14: Driver Wellness, Hours of Service, and Drug/Alcohol Rules
14.1 Hours of Service (HOS) Regulations: 11-Hour, 14-Hour, 30-Minute Break, 60/70-Hour Rules & ELD Mandate 14.2 Driver Physical Qualifications, Medical Certification (Part 391), Fatigue, and Sleep Apnea 14.3 Drug and Alcohol Regulations (49 CFR Part 382): 0.04% BAC Limit, Testing Types, and Drug & Alcohol Clearinghouse
15 Chapter 15: Hazardous Materials Awareness for General CDL
15.1 Hazardous Materials Identification: The Nine Hazard Classes and UN/NA Numbers 15.2 Shipping Papers, Emergency Response Guidebook (ERG), and In-Cab Document Rules 15.3 Placarding Thresholds (Table 1 vs. Table 2, 1,001-lb rule), Bulk vs. Non-Bulk, and Hazmat General Rules
3.4 Putting the Vehicle in Motion: Accelerating, Steering, and Stopping Smoothly
Key Takeaways Explain This Topic AI
Speed up smoothly and gradually; rough acceleration causes mechanical damage and, when pulling a trailer, damages the coupling.
If the drive wheels begin to spin on a slippery surface, take your foot off the accelerator — adding power deepens the traction loss.
Prevent rollback on a grade by partly engaging the clutch before releasing the brake, or by holding with the parking brake or the trailer hand valve until engine power is sufficient.
Hold the steering wheel firmly with both hands on opposite sides of the wheel so a curb or pothole strike cannot tear the wheel out of your grip.
Push the brake pedal down gradually and control the pressure so the vehicle comes to a smooth, safe stop; in a manual transmission push the clutch in when the engine is close to idle.
Last updated: August 2026
Putting the Vehicle in Motion: Accelerating, Steering, and Stopping
Federal knowledge requirements list basic control as its own testable area: starting and shutting down the engine, putting the vehicle in motion and stopping , backing in a straight line, and turning. The starting, backing, and turning pieces are covered elsewhere in this guide. This section covers the part candidates most often skip because it looks obvious — and then miss on the test because the correct answers are counter-intuitive for anyone whose experience is limited to passenger cars.
A loaded combination vehicle can weigh 20 to 30 times what a car weighs. Every input you make is amplified by that mass. Smoothness is not a comfort preference; it is a mechanical requirement.
1. Accelerating
Speed up smoothly and gradually so the vehicle does not jerk. Rough acceleration can cause mechanical damage throughout the driveline — clutch, transmission, driveshaft, and differential all absorb the shock. When you are pulling a trailer, rough acceleration transmits that shock straight into the coupling , and a hammered fifth wheel or pintle hook is a safety defect, not just a maintenance expense.
Accelerating When Traction Is Poor
On rain, snow, ice, gravel, or a wet dock apron, speed up very gradually . If you use too much power, the drive wheels may spin and you can lose control. The correct response when the drive wheels start spinning is simple and non-negotiable:
Take your foot off the accelerator.
Do not add throttle to "push through" the slip, and do not stab the brakes. Reducing power lets the spinning wheels slow down until their rotational speed matches the road speed again and traction returns. Adding power does the opposite: a spinning drive axle on a tractor-trailer is the first act of a drive-wheel skid and a jackknife.
Preventing Rollback
Don't roll back when you start — you may hit the vehicle behind you, and on a grade the roll accelerates fast. Three techniques prevent it:
Manual transmission: partly engage the clutch before you take your right foot off the brake, so the driveline is already loaded when the brake releases.
Parking brake: set it whenever needed to hold the vehicle, and release it only after you have applied enough engine power to keep from rolling back.
Trailer hand valve (trolley valve): on a tractor-trailer so equipped, applying the hand valve holds the trailer brakes while you build engine power.
Rollback is also a scored item on the on-road skills test, so the habit you build now is the one an examiner will grade later.
2. Steering
Hold the steering wheel firmly with both hands, positioned on opposite sides of the wheel. This is not stylistic advice. If you strike a curb or drop a steer tire into a pothole or chuckhole, the impact travels back up the steering linkage and the wheel can pull away from your hands — and a heavy vehicle that steers itself for even half a second at highway speed is already out of its lane.
Practical points that follow from the same principle:
Keep both hands on the wheel through turns, curves, and any maneuver where a surface defect could jolt the steering.
Never rest a hand inside the wheel spokes; a kickback can break a wrist or thumb.
Steer with smooth, deliberate inputs. Quick, sharp steering is one of the four causes of a skid, and in a combination vehicle it is what starts a rollover or trailer swing .
3. Stopping
Push the brake pedal down gradually. The amount of brake pressure you need depends on your speed and how quickly you need to stop, and your job is to control the pressure so the vehicle comes to a smooth, safe stop . Jabbing at the pedal in a heavy vehicle produces nose-dive, cargo shift, and — on a slick surface — wheel lockup.
In a vehicle with a manual transmission , push the clutch in when the engine is close to idle as you come to a stop. Go in too early and you coast without engine braking; go in too late and the engine stalls, which on a tractor-trailer means losing power steering assist and, if it happens mid-intersection, sitting still in traffic.
Two habits belong to every stop:
Fasten your seat belt whenever the vehicle is on the road.
Apply the parking brake whenever you leave your vehicle, without exception.
4. Putting It Together: Common Test Traps
- Situation Wrong instinct Correct action
- Drive wheels spin on a wet ramp Add throttle to power through Take your foot off the accelerator
Starting on an uphill grade in a manual Release brake, then find the clutch Partly engage the clutch first, or hold with the parking brake or hand valve
Steer tire drops into a pothole One-hand grip, correct afterward Both hands, opposite sides, firm grip before the impact
- Coming to a stop in a manual Clutch in early and coast Clutch in when the engine is close to idle
- Loaded trailer, leaving a dock Accelerate briskly to merge Smooth, gradual power to protect the coupling