The Air Resources Board has revised its draft regulatory language for vehicle solar control requirements to specify only solar control requirements for new vehicles windows (glazing). The original proposed regulation contained requirements for both vehicle paint (“cool paint”) and windows to improve their ability to reflect heat from the sun.
|Image from a 2006 Toyota/AIST study comparing conventional and solar reflective paint (SRP). Source: Hashem Akbari, Berkeley Lab (2008). Click to enlarge.|
The earlier version of the proposed regulations triggered a wash of rumors and speculation (incorrect) on the Internet that ARB was going to ban black cars.
The Cool Cars action was identified as an Early Action strategy for the implementation of the California Global Warming Solutions Act, also known as AB 32. Cool Cars, which is to be in place no later than 1 January 2010, is based on measures to reduce the solar heat gain in a vehicle parked in the sun. A cooler interior would make drivers less likely to activate the air conditioner, which in turn increases carbon dioxide emissions.
ARB noted earlier that potential approaches could include reformulation of paint to reflect near-infrared sunlight, parked car ventilation, and solar reflective window glazing. ARB said that cool paints, together with reflective glazing, could reduce the soak temperature of the typical vehicle parked in the sun by 5 to 10 ° C.
In a statement, ARB said that the intent of the paint requirements was to introduce reflective paint (currently used in architectural paints to keep houses and businesses cool) into the automotive arena. The requirement was never at any point to limit consumer color choices or ban any colors.
Based on input from the automotive industry, paint, pigment suppliers, and comments from a public workshop held on 12 March, ARB staff determined that a clear path to achieve solar reflectivity for the darker colors has not yet been identified. Staff plans to address the paint-related portion of the proposal in a future regulatory action.
Staff has also changed the glazing requirements from a reflective (Rds) to a Total Solar Transmission (Tts) specification. This metric more closely aligns with the proposal’s goal of limiting solar transmission into the vehicle.