- Class A: lets you drive a combination of a motor vehicle and a towed vehicle where the towed vehicle's registered gross weight is over 4,600 kg (for example, a tractor-trailer). A Class A licence also covers vehicles in Classes D, G and several others. There is a restricted variant, Class A with condition R, which excludes full air-brake-equipped tractor-trailers but allows lighter combinations.
- Class D: lets you drive a motor vehicle with a registered gross weight over 11,000 kg, or a truck-and-trailer combination where the trailer is 4,600 kg or less. In plain terms, Class D covers the large straight (single-unit) truck. A Class D licence also covers Class G.
Common mistake: assuming a Class D licence lets you pull any trailer. It does not. Once the trailer's registered gross weight passes 4,600 kg, the combination needs Class A, not Class D.
Worked example: You are hired to drive a dump truck with a registered gross weight of 14,000 kg and no trailer. It is a single heavy unit over 11,000 kg, so the correct licence is Class D.