Ohio CDL General Knowledge cheat sheet

Class A combination vehicles: GCWR 26,001 lb or more with towed unit over 10,000 lb; Class B: single vehicle 26,001 lb or more, or towing 10,000 lb or less; Class C: 26,000 lb or less carrying 16+ passengers or placarded hazmat.

Ohio and federal limits: 13 ft 6 in height, 8 ft 6 in width, 53 ft trailer length on designated routes; interstate minimums are 12 ft 6 in height and 8 ft width, so a legal load elsewhere may be overheight in Ohio.

Stopping distance = perception distance + reaction distance + brake lag distance + braking distance; total stopping distance at 55 mph is roughly the length of a football field, and it grows with the square of speed.

Speed limits: 55 mph on most divided highways outside urban areas, 65-70 mph on rural freeways where posted; 55 mph for hazmat placarded loads and for school buses carrying passengers, unless a lower limit is posted.

Blood alcohol: 0.04% for CDL holders in a CMV, 0.08% in a personal vehicle, and 0.02% or any detectable amount for drivers under 21; refusal of a test triggers a one-year CDL disqualification for a first offense.

Hours of service (property): 11-hour driving limit, 14-hour on-duty window, 30-minute break after 8 cumulative driving hours, 60/7 or 70/8 day limits; reset with 34 consecutive off-duty hours.

Out-of-service thresholds: 15 mph or more over the limit, 20% or more of brakes defective, any brake defect on a steering axle, and 20% or more of cargo not secured.

Inspection rule: pre-trip, on-duty, and post-trip inspections are required each day; the post-trip report must be reviewed by the next driver, who signs it.

Following distance: at least one second per 10 ft of vehicle length below 40 mph, and one second per 10 ft plus one extra second above 40 mph; add a second for rain, darkness, or heavy traffic.

Right turns: swing wide or turn from the proper lane only after checking the right side mirror; rear wheels track inside the front wheels, so the off-tracking gap is roughly 2-3 ft per 10 ft of wheelbase.

Downgrade control: select a gear below the speed at which runaway begins before starting down, use engine braking and stab braking, and never coast in neutral; brakes on a long grade fade from heat buildup.

Hydroplaning begins at speeds as low as 30 mph on wet pavement; ease off the accelerator, avoid hard braking, and do not steer sharply until tires regain contact.

Tire failure: hold the steering wheel firmly, stay off the brakes, and let the vehicle slow gradually; for a front tire blowout, accelerate briefly to stabilize before slowing.

Railroad crossings: never stop on the tracks, do not shift gears while crossing, and if a train approaches, stop short and evacuate away from the tracks if the vehicle stalls.

Fire response: pull off the road, shut off the engine, get occupants out and away, and do not open the hood fully if the fire is under it; call 911 and stay clear of fuel and cargo.

Night driving: dim high beams within 500 ft of oncoming traffic and within 200 ft when following; at night, speed should let you stop within the distance your headlights illuminate.

Cargo securement: at least one tiedown per 10 ft of article length, with a minimum of two tiedowns; aggregate working load limit must be at least 50% of the cargo weight.

Headache rack and front-end structure must protect the cab from shifting cargo; cargo cannot extend more than 4 ft ahead of the front bumper or beyond the rear of the vehicle.

Overhang rules: loads may extend up to 3 ft beyond the front and 4 ft beyond the rear before flags, lights, or permits are required; rear overhang over 4 ft needs a red flag by day and a red light at night.

Weight limits: 20,000 lb per single axle, 34,000 lb per tandem axle group, and 80,000 lb gross on the interstate system; bridge formula governs axle spacing.

Pre-trip items: check tire tread depth (4/32 in on steering tires, 2/32 in elsewhere), tire pressure, brake adjustment, lights, mirrors, coupling devices, and load securement.

Brake adjustment: with the brakes released, push the slack adjuster by hand; if it moves more than about 1 in, the brake is out of adjustment and must be corrected before driving.

Air brake warning signals: the low-pressure warning must activate before pressure drops below 60 psi, and the spring brakes should apply between 20 and 45 psi; build to governor cut-out near 120-125 psi.

Hazmat placarding: placards are required for 1,001 lb or more of a Table 2 material, any amount of a Table 1 material, and for 1,001 lb aggregate of Table 2 materials; a placarded load requires a CDL with the hazmat endorsement.