more than 4.6 tonnes. Europe A category CE driving licence is required to drive a tractor-trailer in Europe. Category C (Γ in Greece) is required for vehicles over , while category E is for heavy trailers, which in the case of trucks and buses means any trailer over . Vehicles over —which is the maximum limit of B license—but under can be driven with a C1 license. Buses require a D (Δ in Greece) license. A bus that is registered for no more than 16 passengers, excluding the driver, can be driven with a D1 license. New Zealand In New Zealand, drivers of heavy vehicles require specific licenses, termed as classes. A Class 1 license (car license) will allow the driving of any vehicle with Gross Laden Weight (GLW) or Gross Combination Weight (GCW) of or less. For other types of vehicles the classes are separately licensed as follows: Class 2 – Medium Rigid Vehicle: Any rigid vehicle with GLW or less with light trailer of or less, any combination vehicle with GCW or less, any rigid vehicle of any weight with no more than two axles, or any Class 1 vehicle. Class 3 – Medium Combination Vehicle: Any combination vehicle of GCW or less, or any Class 2 vehicle. Class 4 – Heavy Rigid Vehicle: Any rigid vehicle of any weight, any combination vehicle which consists of a heavy vehicle and a light trailer, or any vehicle of Class 1 or 2 (but not 3). Class 5 – Heavy Combination Vehicle: Any combination vehicle of any weight, and any vehicle covered by previous classes. Class 6 – Motorcycle. Further information on the New Zealand licensing system for heavy vehicles can be found at the New Zealand Transport Agency. Taiwan The Road Traffic Security Rules (道路交通安全規則) require a combination vehicle driver license () to drive a combination vehicle (). These rules define a combination vehicle as a motor vehicle towing a heavy trailer, i.e., a trailer with a gross weight of more than . United States Drivers of semi-trailer trucks generally require a Class A commercial driver's license (CDL) to operate any combination vehicles with a gross combination weight rating (or GCWR) in excess of if the gross vehicle weight rating (GVWR) of the towed vehicle(s) is in excess of . Some states (such as North Dakota) provide exemptions for farmers, allowing non-commercial license holders to operate semis within a