each wheeled tractor category described in points 2 to 8 is supplemented at the end by an ‘a’ or ‘b’ index according to its design speed:
déantar gach catagóir tarracóra ar rothaí a thuairiscítear i bpointe 2 go pointe 8 a fhorlíonadh ag an deireadh le hinnéacs “a” nó “b” de réir a luas dearaidh: