There are hundreds of different types of vehicles in the world and these also have subcategories, various models, etc. Unless you are road savvy and have had a considerable exposure in the vehicle field or you are a mechanic you may not know details of most of the types.
Most people get the idea that there are basic categorizations of vehicles based on the common characteristics when they are applying for the diving license. You would have got the license to drive either one or more categories and when earning the same you would have got a basic idea about the difference between a light vehicle and a heavy vehicle.
When we say heavy vehicles one of the first thing that comes in to our minds are the huge trailers that carry containers. As you rightly guessed, the differentiating factor is mainly the size or the weight. A truck mechanic Swan Hill is the best person to explain this in detail.This type of vehicles are also differentiated based on the task for which they are used. For example, some of the rules that apply for other heavy vehicles may not, in some cases, apply to buses even though they are all large vehicles.
Due to these differences you need specialized skills if you are driving a heavy vehicle. There are also different speed limits to ensure the safety of the others as well as the driver of the vehicle. These should also undergo regular truck repairs even for minor faults as the accidents will cause more damage than a regular vehicle.You would of course know that driving a huge truck or a bus is not an easy task. The load you are carrying may also add to the burden as the way the vehicle behaves in a certain condition may differ when you are carrying a load of goods than it would when you are driving empty.Turning, reversing and even parking takes a lot of skills and just mere driving ability is insufficient.
These are the normal vehicles such as the cars, vans, pickup trucks, etc. Small lorries are also considered as light vehicles but you may want to check with your motor registration agency before purchasing if you are not sure so that you will not end up with a vehicle but you do not have the appropriate license to drive it.The driving test is also less complex as this type of vehicles do not have many complications. A regular check up at the service may be all you need to ensure that your vehicle is road safe.
Further, the applicable rules and regulations are fairly relaxed and the speed limits are also generally higher than that for the heavy vehicles as the management is not so difficult.
It would be fascinating to do some research if you are interested in finding more details of the aforementioned differentiation.