Regulation 55 of the Principal Regulations is amended as follows:(a) by omitting from subregulation (1) "vehicle" and substituting "light vehicle" ;(b) by omitting from subregulation (2) "vehicle" first occurring and substituting "light vehicle" ;(c) by omitting paragraph (a) from subregulation (2) and substituting the following paragraph:(a) across the tyre width that normally comes into contact with the road; and(d) by omitting from subregulation (3) "vehicle" and substituting "light vehicle" .