Oklahoma CDL General Knowledge cheat sheet

Total stopping distance = perception distance + reaction distance + brake lag distance + braking distance; at 55 mph a loaded rig needs roughly the length of a football field to stop.

Perception distance is the ground covered in the ~3/4 second before you recognize a hazard; reaction distance covers the ~3/4 second before the brake is applied.

Brake lag for air brakes is about 3/4 second (roughly 60 feet at 55 mph) before braking force begins; hydraulic brakes have no air lag.

Speed limits: 55 mph on two-lane undivided roads, 65 mph on rural interstates and turnpikes, 75 mph on the Turner, Will Rogers, and H.E. Bailey turnpikes, and 70 mph on the Muskogee Turnpike.

Minimum following distance for a CMV under 40 feet: one second for each 10 feet of vehicle length plus one second; a 60-foot rig at 55 mph needs about 7 seconds.

Add one extra second of following distance for speeds above 40 mph, and one more second for rain, snow, ice, fog, or heavy traffic.

Use the 4-second rule (or one second per 10 feet plus one) for vehicles under 40 feet; double following distance on slippery roads.

Skid recovery: stop braking, turn the steering wheel in the direction you want to go, and avoid hard braking until the tires regain traction.

Hydroplaning can begin at speeds as low as 30 mph with worn tires; ease off the accelerator and do not brake hard.

Aggregate working load limit (WLL) of tiedowns must be at least 50% of the cargo weight for cargo not needing a specific securement method.

Cargo must be secured with at least one tiedown for articles 5 feet or shorter and 1,100 pounds or less; two tiedowns for articles longer than 5 feet or heavier than 1,100 pounds.

Cargo must be secured with at least four tiedowns if it is longer than 10 feet, regardless of weight.

Tiedowns must be attached to the vehicle frame or to anchor points with a WLL at least 50% of the tiedown's WLL.

Inspect cargo and tiedowns within the first 50 miles of travel, then every 150 miles, every 3 hours, or at every change of duty status, whichever comes first.

Front-end structure must prevent cargo from shifting forward more than 3 feet during a 20 mph deceleration; rear structure must withstand a 20 mph impact.

Cargo must not extend more than 3 feet beyond the front bumper, more than 4 feet beyond the rear of the vehicle, or more than 8 feet 6 inches in overall width without a permit.

A red flag at least 18 inches square must mark the rear of loads extending 4 feet or more beyond the rear; at night a red light visible for 500 feet is required.

Never overload an axle or tire; check the gross vehicle weight rating (GVWR), gross axle weight rating (GAWR), and tire load limits before loading.

Air pressure must build from 85 to 100 psi within 45 seconds at fast idle with the engine at 600-900 rpm; if it takes longer, the system may have a leak.

With the engine off and the service brakes released, pressure should not drop more than 3 psi in one minute for a single vehicle, or 4 psi for a combination vehicle.

With the brakes applied, leakage should not exceed 4 psi in one minute for a single vehicle or 6 psi for a combination vehicle.

The low-air warning buzzer and light must activate before pressure drops below 60 psi.

The spring brakes must apply automatically when pressure falls to between 20 and 45 psi (typically around 30 psi).

The governor cut-out pressure is typically 120-125 psi; cut-in is typically 100 psi.

Safety valve releases at about 150 psi to protect the system from overpressure.

Before driving, perform the three-part air brake check: leakage test, low-air warning test, and spring brake test; also check the slack adjusters and brake drums.

Fan the brakes to reduce pressure, then observe the gauge during the warning and spring brake tests; do not drive with a low-air warning.

The tractor protection valve closes and applies trailer spring brakes when pressure drops to 20-45 psi, protecting the tractor's air supply.

The trailer hand valve (johnson bar) should never be used for parking; use it only to test trailer brakes.

The emergency line (red) supplies air to the trailer; the service line (blue) carries the brake application signal.

Check the coupling by pulling the tractor gently forward with the trailer brakes locked; the trailer should not move and the tractor should not pull free.

Fifth wheel jaws must be locked around the kingpin; check by tugging the release handle and inspecting the gap.

The landing gear must be fully raised after coupling; failure to raise it can damage the gear or cause a crash.

When backing a trailer, turn the steering wheel in the direction you want the trailer to go; use the mirrors and GOAL (get out and look).

Off-tracking: a combination vehicle's rear wheels follow a shorter path than the front; a 55-foot trailer can off-track by 3-5 feet in a turn.

Swing wide on turns because the rear of the trailer swings outward; the longer the wheelbase, the more the trailer cuts the corner.

The seven-step inspection includes: vehicle overview, engine compartment, walk-around (front, sides, rear), lights, brake check, and in-cab inspection.

Check engine oil, coolant, power steering fluid, and windshield washer fluid with the engine off and the vehicle on level ground.

Check belt tension and condition; a glazed or cracked belt must be replaced.

Inspect tires for tread depth (at least 4/32 inch on front steer tires, 2/32 inch on other tires), cuts, bulges, and proper inflation.

Check the brake system: slack adjusters should not move more than about 1 inch when pulled by hand, and brake drums should be free of cracks.

Check lights: headlights (high and low), turn signals, four-way flashers, brake lights, clearance lights, and reflectors.

Check the coupling system on combination vehicles: fifth wheel jaws locked, kingpin secure, safety latch closed, and air lines connected.

Check the emergency equipment: fire extinguisher, spare fuses, and warning triangles (three required for a CMV).

During the in-cab inspection, check the seat belt, horn, wipers, gauges, mirrors, and steering wheel play (no more than 10 degrees free play).

Before starting, fasten your seat belt, adjust the seat and mirrors, and check that the parking brake is set.

Start the engine and check that the oil pressure gauge rises and the alternator gauge shows charging; if not, shut down.

Use the parking brake when parked; on a grade, chock the wheels and turn the front wheels toward the curb (downhill) or away from the curb (uphill).

When backing, use the mirrors and a spotter; if you cannot see the spotter, stop.

Use the GOAL method (Get Out And Look) whenever you are unsure about clearance.

Steering: use both hands, keep the wheel steady, and avoid sudden movements that can cause a rollover.

Braking: apply the brakes smoothly and progressively; do not pump air brakes unless you need to build pressure.

On a downgrade, select a lower gear before starting down and use engine braking; do not ride the brakes.

When stopped in traffic, leave enough space ahead to maneuver around a stalled vehicle (at least one car length).

Use the clutch only to start from a stop and to shift; do not slip the clutch or rest your foot on the pedal.

Shift up in the correct sequence; do not skip gears when downshifting unless you are sure of the gear range.

Double-clutching: press the clutch, shift to neutral, release the clutch, press the clutch again, and shift to the next gear.

Match engine speed to road speed when downshifting; a tachometer reading in the correct range prevents lugging and over-revving.

Do not coast in neutral or with the clutch depressed; you lose engine braking and control.

On a downgrade, downshift before the grade; do not wait until you are already moving fast.

Use the tachometer: shift up before the engine reaches the governed rpm, and downshift before it drops below the torque range.

If you miss a gear, do not force it; stop, shift to neutral, and start over.

Automatic transmissions: use the selector to hold a lower gear on grades; do not ride the brakes.

Keep your eyes moving and scan 12-15 seconds ahead of your vehicle; at highway speed that is about a quarter mile.

Use the mirrors every 5-8 seconds; check both sides and the rear.

Signal your intentions at least 100 feet before turning or changing lanes; use your four-way flashers when stopped or moving slowly.

Flash your headlights to warn oncoming drivers of your presence, but do not use them to communicate anger.

Tap your brakes to warn following drivers that you are slowing; this also activates the brake lights.

Use the horn only to warn others of danger; do not use it to express frustration.

At night, dim your high beams when meeting or following another vehicle; use low beams in fog, rain, or snow.

When passing, check mirrors, signal, and move into the passing lane only when you can see the passed vehicle in your mirror before returning.

Communicate with other drivers using turn signals, brake lights, horn, and headlights; make eye contact when possible.

Following distance: one second per 10 feet of vehicle length plus one second; add one second above 40 mph and one more in bad weather.

At 55 mph, a 60-foot rig needs about 7 seconds of following distance; at 65 mph, about 8 seconds.

Stop at least 10 feet from railroad tracks; if you are carrying hazardous materials, stop 15-50 feet from the tracks.

When entering a curve, slow down before the curve and accelerate gently through it; do not brake hard in the curve.

Space to the sides: keep at least one lane width of space on each side; avoid driving next to other large vehicles.

Space ahead: leave enough room to stop if the vehicle ahead stops suddenly; do not tailgate.

Space behind: maintain a following distance and avoid being tailgated; if tailgated, increase your own following distance and do not brake hard.

Speed control on grades: downshift before the downgrade and use engine braking; do not exceed the safe speed for the grade.

In construction zones, reduce speed and obey flaggers; fines are doubled in work zones in Oklahoma.

Hazardous materials are identified by placards, labels, and shipping papers; the shipping papers must be within reach while driving.

Placards must be displayed on all four sides of the vehicle for most hazmat loads; the placard must match the hazard class.

The emergency response guidebook (ERG) provides initial response information for hazmat incidents; know how to use it.

When transporting hazmat, stop 15-50 feet from railroad tracks and check for trains before crossing.

Never smoke or use open flames near hazardous materials; keep the engine off during loading and unloading.

If a hazmat leak or spill occurs, stop, secure the area, and notify authorities; do not attempt to clean up unless trained.

Fire extinguisher: a minimum 10 BC rating is required for vehicles carrying hazardous materials; check the gauge monthly.

Warning triangles: place them 10 feet, 100 feet, and 200 feet behind the vehicle (or 100 feet, 200 feet, and 500 feet on a divided highway).

In an emergency, stop, set the parking brake, turn off the engine, and evacuate if necessary; call 911 and report the hazard class and UN number.