The classical school emphasizes production of goods and services as the key focus of economic analysis. Neoclassical economics focuses on how individuals operate within an economy. As such, the neoclassical school emphasizes the exchange of goods and services as the key focus of economic analysis.. (Source : Difference Between Classical & Neoclassical Economics | eHow) Here's information about the dates of emergence of neoclassical economics:
A random sampling of other states indicates the issue is mixed. For example, Illinois taxes the equipment if it is used in a manufacturing process. In Maine, there is no exemption. In Connecticut, all fire safety equipment is exempt.
California has a sniffer test semi-anually and at resale time. Exempt from that test are cars less than five years old and '75 model year and older. Motorcycles and diesel cars of any year are exempt too. Tampering with emissions equipment is illegal.