Section 6 - Combination Vehicles

2005 Commercial Driver’s License Manual


Figure 6.2
Stop Using the Brake.

Release the brakes to get traction back. Do not use the trailer handbrake (if you have one) to "straighten out the rig" This is the wrong thing to do since the brakes on the trailer wheels caused the skid in the first place. Once the trailer wheels grip the road again, the trailer will start to follow the tractor and straighten out.
6.1.6 – Turn Wide
When a vehicle goes around a corner, the rear wheels follow a different path than the front wheels. This is called off-tracking or "cheating" Figure 6.3 shows how off-tracking causes the path followed by a tractor to be wider than the rig itself. Longer vehicles will offtrack more. The rear wheels of the powered unit (truck or tractor) will offtrack some, and the rear wheels of the trailer will offtrack even more. If there is more than one trailer, the rear wheels of the last trailer will offtrack the most. Steer the front end wide enough around a corner so the rear end does not run over the curb, pedestrians, etc. However, keep the rear of your vehicle close to the curb. This will stop other drivers from passing you on the right. If you cannot complete your turn without entering another traffic lane, turn wide as you complete the turn. This is better than swinging wide to the left before starting the turn because it will keep other drivers from passing you on the right. See Figure 6.4.



Table of contents
Who needs a commercial driver license?
Commercial learner permit (clp)
Farm-related service industry (frsi) waiver
Codetpnhxscode
General requirements
Commercial driver license (cdl)
Safety inspection
Texas drivers applying fora
Others applying fora commercial driver license
Disqualifications
Are the tests difficult?
Section 1 introduction
Figure 1.1 note:
School bust test
What sections should you study?
Interstate non-excepted
Intrastate non-excepted
Section 1 - introduction
The irp registrant and the ifta licensee may
Figure 1 – individual vehicle mileage & fuel record (example)
Vehicle inspection.
Section 2 – driving safely
Figure 2.1suspension system defects.
Exhaust system defects.
Approaching the vehicle.
Step 2: check engine compartment
Page 2-3 version: july 2013
Look at the gauges
Check condition of controls.
Left front side
Step 6: check signal lights
Step 7: start the engine and check
Test service brake stopping action
Safety inspection.
Back slowly.
Knowing when to shift up.
Basic procedures for shifting down
Before starting down a hill.
Subsections 2.2 and 2.3
Importance of looking far enough ahead.
Look for traffic.
Mirror adjustment.
Check your vehicle.
Lane changes.
Stopping on the road
Don't direct traffic.
When it's hard to see.
Reaction distance
The effect of vehicle weight on stopping
Just after rain begins
Figure 2.12 2.7.2 – space behind
Page 2-16 version: july 2013
Staying centered in a lane.
Strong winds.
Seeing hazards lets you be prepared.
Learning to see hazards.
Work zones.
Foreign objects.
Off ramps/on ramps.
Delivery trucks can present a hazard.
Pedestrians and bicyclists can also be
Slow drivers.
Drivers in a hurry.
Driver body movement as a clue.
Subsections 2.7 and 2.8
Subsections 2.9 and 2.10
Fatigue and lack of alertness.
Warning signs of fatigue
Maintaining alertness while driving
Poor lighting.
Drunk drivers.
Other lights.
Avoid blinding others.
Use high beams when you can.
Wipers and washers.
Lights and reflectors.
Radiator shutters and winterfront.
Slippery surfaces.
Adjust space to conditions.
Engine oil.
Engine belts.
Go slowly enough to prevent overheating.
Passive crossings.
Advance warning signs.
Cross-buck signs.
Don't rely on signals.
Subsections 2.15 and 2.16
Keep both hands on the steering wheel.
Where to steer.
Leaving the road.
Returning to the road.
Controlled braking.
Find an escape route.
Respond to tire failure.
Check the tires.
Abs won’t allow you to drive faster
Abs won’t change the way you normally
Over-steering.
Figure 2.19
Follow safe procedures.
Pull off the road.
Extinguish the fire.
Class/type of fires
Figure 2.21 section 2 – driving safely
How alcohol works.
What determines
How alcohol affects driving.
What is a drink
Effects of increasing
To communicate the risk.
Figure 2.24 2.23.3 – lists of regulated products
Subsections 2.22 and 2.23
Figure 3.2 section 3 - transporting cargo safely
Section 3 test your knowledge
Section 3 - transporting cargo safely
Figure 4.1 4.2.2 – forbidden hazardous materials
Section 4 - transporting passengers safely
The most common bus accidents.
Stop at drawbridges.
Section 4 test your knowledge
Figure 5.1 section 5 – air brakes
S-cam brakes.
Figure 5.2 wedge brakes.
Modulating control valves.
Figure 5.3 5.1.16 – antilock braking systems (abs)
Section 5 – air brakes
Check brake drums
Test low pressure warning signal.
Check rate of air pressure buildup.
Test air leakage rate.
Check air compressor governor cut-in and
Test parking brake.
Section 6 - combination vehicles
Figure 6.3 figure 6.4
Subsection 6.1
Emergency air-line.
Figure 6.6 section 6 - combination vehicles
Subsection 6.2
Figure 6.7 6.3.2 – braking with abs
Step 5. secure tractor
Step 8. supply air to trailer
Step 9. lock trailer brakes
Step 12. secure vehicle
Step 14. connect the electrical cord and check
Step 16. remove trailer wheel chocks
Step 3. chock trailer wheels
Step 5. disconnect airlines and electrical
Test tractor protection valve.
Test trailer emergency brakes.
Subsection 6.5
Section 7 - doubles and triples
Connect converter dolly to front trailer
Uncouple rear trailer
Uncouple triple-trailer rig
Coupling system areas
Double and triple trailers
Section 7 test your knowledge
Figure 8.1 8.2.1 – high center of gravity
Section 8 - tank vehicles
Section 9 - hazardous material
Transportation—who does what
Hazardous materials class
Examples of hazmat placards
The hazardous materials table.
Appendix b to 49 cfr 172.101 – list of marine
Special instructions:
Placard table 2
Figure 9.8 section 9 - hazardous material
Subsections 9.1, 9.2, and 9.3
No smoking.
Use closed cargo space.
Class 4 (flammable solids) and class 5
Class 8 (corrosive) materials.
Class 2 (compressed gases) including
Class 7 (radioactive) materials.
Do not load table
Figure 9.9 mixed loads.
Subsection 9.5
Emergencies 9.7.1 – emergency response guidebook
Page 9-15 version: july 2013
Class 1 (explosives).
Class 7 (radioactive materials).
National response center
Figure 9.10 classes of hazardous materials
Figure 9.11 subsections 9.6 and 9.7
Radioactive separation
Division – a subdivision of a hazard class. epa
Gross weight or gross mass
Hazardous substance
Limited quantity
Outage or ullage
Proper shipping name
Section 10 – school buses
Additional procedures for students that must
Dropped or forgotten objects.
Handrail hang-ups.
Determine need to evacuate bus.
Mandatory evacuations.
Active crossings.
Figure 10.5
Figure 10.7 flashing red light signals.
Approaching the crossing
Crossing the track
Police officer at the crossing.
Containment or storage areas.
Power steering fluid
Oil pressure gauge
Ammeter/voltmeter
Lights/reflectors/reflector tape condition
Horn check that air horn and/or electric horn work. heater/defroster
Section 11 - vehicle inspection
Steering box/hoses
Shock absorbers
Hub oil seals/axle seals
Door(s)/mirror(s)
Splash guards
Catwalk/steps
Hitch release lever
Locking pins (fifth wheel)
Tongue storage area
Lights/reflectors
Landing gear
Emergency exits
Level/air leaks
Remainder of vehicle
Outside vehicle observations (looks)
Final position
Figure 12.2: offset back/right
Section 13 – on-road driving
Special permits.
Two way roadway
Lighting and reflectors.
Divided highway
Implements of husbandry.
Dard vehicle size requirements
School buses, recreational vehicles, and others
Test your knowledge
Texas commercial driver license
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