Neon underglow lights come in a variety of brands and colors, and the legality of their use varies by state. In Iowa, there are no laws specifically addressing their use; however, there are statutes that restrict the colors of lights displayed on public roads. That said, it is legal to purchase, sell and install neon underglow lights as long as they meet the requirement of the law.
Color of Lighting Devices
Section 321.422 of the Merged Iowa Code (MIC), prohibits displaying a red light from the front of any motor vehicle being operated on a public road except those authorized to do so. Section 321.404 requires lights on the rear of a vehicle to be either red or amber, other than back-up lamps, which may only be lit while the vehicle is moving in reverse in accordance with Section 321.408. Additionally, blue lights may not be used anywhere on a motor vehicle unless authorized.
Other than signal or hazard lamps, flashing lights of any color are prohibited on vehicles except those authorized to be equipped with them, such as emergency vehicles, school buses and recovery vehicles.
Violating any of these sections results in a traffic infraction and a fine. Using flashing lights, blue lights or rear lights that are any color other than red or amber results in a $20 fine. Displaying a red light visible from the front of the vehicle yields a fine of $10.