A nit is a measure of luminous intensity per unit area. It is used to indicate the brightness of flat screen displays such as electronic message boards, computers, televisions, etc.
One nit is equivalent to one candela per square meter. A candela is a unit of luminous intensity approximately equal to the luminous intensity emitted by one common candle. If a surface area of one square meter were positioned one meter away from a candle, the luminous intensity of that square meter would be approximately one nit.
In 2016, the Fountain Hills lighting and sign ordinances were updated to address new technologies. One rapidly evolving technology is electronic message boards, which have become less expensive and capable of brighter light output. Arizona State University concluded from a research study that a brightness above 100 nits causes temporary blindness for drivers. For that reason, communities across the country are adopting the 100-nit maximum for electronic message boards and Fountain Hills incorporated this guideline in its sign ordinance.
From the Town of Fountain Hills Sign Ordinance: Led signs shall not exceed the maximum lumination level of 100 nits.