special-purpose vehicle
Refers to vehicles designed for specific functions, such as construction machinery, emergency vehicles, or agricultural equipment, rather than ordinary passenger cars.
To get a license for special-purpose vehicles, you need special training.
Many special-purpose vehicles are lined up at the construction site.
Similar in meaning, but 特殊車両 is a broader term that can include non-automotive special vehicles, while 特殊自動車 specifically refers to motor vehicles.
small special-purpose vehicle
Compound of 特殊 (special) + 自動車 (automobile). The term is a straightforward modern coinage.