Traffic Law, Licence Classes and Vehicle Classification for Medium Vehicles
The class boundaries decide everything else
The exam opens with classification because speed limits, road restrictions and inspection intervals are all keyed to it. A vehicle is 大型 when gross weight reaches 11 t, payload 6.5 t, or capacity 30 people. Under those, but meeting any one of gross 5 t, payload 3 t, or capacity 11 people, it is 中型. The three figures work as "or", not "and": crossing a single threshold moves the vehicle up a class.
What the licence covers
A full 中型免許 (age 20, plus two years of prior ordinary-licence history) covers 中型, 準中型, 普通, 小型特殊 and 原付. The older 中型8t限定 licence, issued to people who held an ordinary licence before the 2007 change, stops at gross 8 t, payload 5 t and capacity 10. "Under" is strict: a vehicle plated at exactly 8.00 t is outside it.
Speed and road use
Statutory limits are 60 km/h on general roads and 100 km/h on expressways, with posted signs overriding both. Certain heavy goods categories, such as 特定中型貨物, are capped lower on expressways, so read the sign rather than trusting the class alone.
Worked example
A 車検証 shows gross weight 7.8 t, payload 4.5 t, capacity 3. Both gross and payload exceed the 中型 thresholds and neither reaches 大型, so the vehicle is 中型. Can an 8t-limited holder drive it? Gross 7.8 < 8 and payload 4.5 < 5, so yes - but if the same vehicle were plated at 8.2 t gross, the answer flips.
Traps
Confusing 車両総重量 with 最大積載量; assuming 中型 covers 大型特殊; thinking 8t限定 allows exactly 8 t; ignoring the expressway speed exception for heavy goods vehicles.