I. No person shall drive a motor vehicle upon any way unless each tire mounted thereon has a minimum tread depth of not less than 2/32 of an inch. II. Notwithstanding any other provision of law to the contrary, this section shall not apply to: (a) Commercial motor vehicles, as defined in RSA 259:12-e, that exceed 10,000 pounds in weight. (b) School buses, as defined in RSA 259:96, that exceed 10,000 pounds in weight. (c) Mixed use school buses, as defined in RSA 259:96-a, that exceed 10,000 pounds in weight.