This is an unusual exception to the general rule in the United States.
Heavy-duty trucks such as the Ford Super Duty and Chevrolet Silverado HD and GMC Sierra HD often have small amber or red lamps on their roofs. This is because vehicles with a width of over 80 inches are required to have this lighting. This regulation is generally applicable to pickups with wider rear fenders. However, GM Authority found an unusual exception to this rule.
These lamps are now illegal under a California motor vehicle rule. This is a strange reason considering their widespread use in America. According to the code, “light bars” are prohibited from emitting illumination that emits amber, red or blue. The individual roof-mounted lamps would not seem to be in compliance with the definition of “light bar”, but regulators disagree.
It is quite common in the United States to not be able show red-and blue lights because these colors are used by emergency services such as fire and police departments. Regulators don’t want to confuse motorists by allowing vehicles to display these shades.
Some members of the Moto1.com team hail from California, so they have additional insight. Parking meters are monitored by people who drive cars with amber lights. Therefore, it makes sense that the state would not want any other vehicles with this illumination on the roads.
“For example in California, local regulations dictate that our Sierra HD single-rear-wheel trucks do not come with amber roof markers lamps,” a spokesperson for GMC told GM Authority.
The 2021 Chevrolet Silverado HD Carhartt Edition is in a similar position (gallery below), because it has amber roof lights. This special Chevy model is not being sold in California.