Any motor vehicle may be operated under the conditions specified in section 321.384 when equipped with two lighted lamps upon the front thereof capable of revealing persons and objects seventy-five feet ahead in lieu of lamps required in sections 321.409 and 321.415, or section 321.417, provided, however, that at no time shall it be operated at a speed in excess of twenty miles per hour.
Iowa Code § 321.418
Referred to in §321.1