off-highway business use
(i)The term “off-highway business use” shall include any use in a vehicle which meets the requirements described in clause (ii). (ii)The requirements described in this clause are— (I)the design-based test, and (II)the use-based test. (iii)For purposes of clause (ii)(I), the design-based test is met if the vehicle consists of a chassis— (I)to which there has been permanently mounted (by welding, bolting, riveting, or other means) machinery or equipment to perform a construction, manufacturing, processing, farming, mining, drilling, timbering, or similar operation if the operation of the machinery or equipment is unrelated to transportation on or off the public highways, (II)which has been specially designed to serve only as a mobile carriage and mount (and a power source, where applicable) for the particular machinery or equipment involved, whether or not such machinery or equipment is in operation, and (III)which, by reason of such special design, could not, without substantial structural modification, be used as a component of a vehicle designed to perform a function of transporting any load other than that particular machinery or equipment or similar machinery or equipment requiring such a specially designed chassis. (iv)For purposes of clause (ii)(II), the use-based test is met if the use of the vehicle on public highways was less than 7,500 miles during the taxpayer’s taxable year. This clause shall be applied without regard to use of the vehicle by any organization which is described in section 501(c) and exempt from tax under section 501(a). (f)