Ontario Class A Commercial flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Governor cut-out pressure

The pressure at which the air compressor stops pumping, typically 120-145 psi; when pressure drops about 20-25 psi below this point, the governor restarts the compressor.

Static air leak test

With the system fully charged and the engine off, hold the service brake applied for one minute; pressure loss must not exceed 4 psi on a single vehicle.

Low-air warning

A warning device that must activate before system pressure drops below 60 psi, alerting the driver that the spring parking brakes will soon apply automatically.

Slack adjuster free stroke

With the brakes released, the push rod travel measured at the slack adjuster should not exceed about 1 inch (25 mm); excessive stroke indicates the brakes need adjustment.

Tire tread minimum

Commercial vehicle tires need at least 3.2 mm (4/32 in) tread on steering axles and 1.6 mm (2/32 in) on all other positions to be legally operable.

Thirteen-item pre-trip

Ontario requires a daily inspection covering brakes, steering, lights, tires, wheels, mirrors, windshield, horn, exhaust, fuel system, coupling devices, safety devices, and load security.

Daily driving limit

A driver must not drive after 13 hours of driving or 14 hours of on-duty time in a day, and must take at least 8 consecutive hours off duty before the next day.

Thirty-minute break rule

After 8 hours of on-duty time, a driver must take at least 30 consecutive minutes off duty, in a sleeper berth, or on duty not driving before driving again.

Cycle limits

A driver may not accumulate more than 70 hours of on-duty time in 7 consecutive days (cycle 1) or 120 hours in 14 days (cycle 2) without a reset.

Log retention period

Daily logs and supporting documents must be kept for at least 6 months and produced on demand during a roadside inspection or carrier audit.

Electronic logging device

An ELD automatically records driving time and duty status for federally regulated carriers; paper logs may still be used by Ontario-only operators under certain conditions.

Tiedown aggregate WLL

The sum of the working load limits of all tiedowns must equal at least 50% of the cargo weight, and each tiedown must be attached to a securement point on the vehicle.

Forward restraint force

Cargo securement must withstand a forward deceleration force of 0.8 g, a rearward force of 0.5 g, and a lateral force of 0.5 g of the cargo weight.

Tiedown count rule

Articles up to 1.52 m long and 500 kg need one tiedown; 1.52-3.04 m need two; longer articles need an additional tiedown every 3.04 m.

Rear overhang limit

A load may not extend more than 35% of the wheelbase or 4.65 m behind the rear axle, whichever is less, unless an oversize permit is held.

Ontario maximum width

The legal maximum vehicle width without a permit is 2.6 m (8 ft 6 in); wider loads require an oversize permit and possibly pilot vehicles.

Ontario maximum height

The legal maximum vehicle height without a permit is 4.15 m (13 ft 8 in); taller loads need a permit and may require route surveys and escorts.

Maximum gross weight

Ontario allows a maximum gross vehicle weight of 63,500 kg on designated highways, subject to axle group limits based on axle spacing.

Steer axle limit

The maximum weight on a steering axle in Ontario is 5,500 kg, and tire and manufacturer ratings may impose a lower limit.

Tandem axle group limit

A tandem axle group is limited to 17,000 kg, while a tridem group is limited to 24,000 kg, with exact limits depending on axle spread.

Tug test

After coupling, pull forward gently in low gear with the trailer brakes set; if the tractor moves without resistance, the fifth wheel is not locked.

Fifth wheel visual check

After the tug test, visually confirm the locking jaws are closed around the kingpin and the release handle is in the locked position before driving.

Air line colour coding

The red line is the emergency (supply) line and the blue line is the service line; they must be connected to matching couplers and supported to prevent dragging.

Uncoupling sequence

Set the trailer brakes, lower the landing gear, disconnect the air lines and electrical cord, then pull the tractor forward slowly to release the fifth wheel.

Off-tracking

The rear wheels of a tractor-trailer follow a tighter path than the front wheels, so drivers must swing wide on turns and allow clearance for the trailer's rear.

Following distance

A loaded tractor-trailer needs at least 4-6 seconds of following distance in good conditions, and this should be doubled in rain, snow, or ice.

No-Zone blind spots

Blind spots extend up to 6 m ahead of the cab, 9 m behind the trailer, and along both sides; other drivers should never linger in these areas.

Downgrade gear selection

Select a lower gear before descending a grade and use engine braking; continuous service brake use can overheat the brakes and cause brake fade.

Annual safety inspection

Commercial vehicles require a safety inspection certificate renewed every 12 months; the certificate must be carried in the vehicle and produced on demand.

Brake fade symptoms

Overheated brakes produce a soft or low pedal, longer stopping distance, and a burning smell; the driver should allow the brakes to cool and use a lower gear.

Steer tire blowout response

Hold the steering wheel firmly, avoid hard braking, ease off the accelerator, and steer to a safe stop; sudden braking can cause loss of control.

Roadside inspection levels

Level I is a full inspection, Level II a walk-around, Level III driver and vehicle, Level IV special, and Level V vehicle only; drivers must comply and produce documents.