Haul trucks are off-road, heavy-duty dump trucks specifically engineered for use in high-production mining and exceptionally demanding construction environments. Most are dual axle; at least two examples of tri-axles were made in the 1970s. Haul trucks are denominated by their payload capacity, by weight (variously in tons, tonnes, and kg).

Most haul trucks have a two-axle design, but two well-known models from the 1970s, the 350T Terex Titan and 235T WABCO 3200/B, had three axles. ^[2] Haul truck capacities range from 40 short tons (36.3 t; 35.7 long tons) to nearly 500 short tons (454 t; 446 long tons).

An example on the smaller end is the Caterpillar 775 (rated at 70 short tons [62 long tons]).^[3] Quarry operations (which produce payloads that have value) are typically employ smaller trucks^[why?] than mining operations (such as removing undesirable overburden, an expense).^{[citation needed]}

Haul trucks can generally be distinguished from standard dump trucks by:

• Being far too large to travel legally on public roads
• Having a dump body made of exceptionally strong steel plate that extends over the cab to protect it, angled upright at its end (or entirely) to aid in dumping; some are heated by exhaust gases to prevent loads from sticking or freezing to the bed;
• Having a driver's cab narrower than its body;
• No axle suspension;
• Limited speed and operating range;
• Special off-road only tires;
• A ratio of dead weight to payload not exceeding 1:1.6^{[citation needed]}

Most large haul trucks use some form of traction motors coupled to regenerative brakings for power, braking, or both.

Haul trucks are classified by:

• Type of unloading (dump or rear-eject);
• Direction of discharge (side, rear);
• Type of body (hopper, platform, sliding hopper, sliding platform).

The largest, highest-payload-capacity haul trucks are referred to as ultra class trucks. The ultra class includes all haul trucks with a payload capacity of 300 short tons (270 long tons) or greater.^[4] As of October 2013^[update], the BelAZ 75710 has the highest payload capacity, 450 metric tons (440 long tons; 500 short tons).^[5]

Look up long haul in Wiktionary, the free dictionary.

• Articulated hauler
• Dumper
• Haul road
• Rear-eject haul truck bodies
• Unit Rig