These are classified as "agricultural equipment", and as such they of course have access to most of the road network (not major highways) and do not need to go fast. Only "unnecessary obstruction" of traffic is illegal, "obstruction for reasonable cause" is perfectly fine.

The thing that annoys me is that there is not even cursory control that these cars are used in connection with agriculture. It was fine in the past, because it was relatively rare that the regulation was abused. After a recent change in the law that made it cheap/easy to convert regular cars, it has become a menace.

For cyclists, too?