If California regulators get their way, auto makers may soon be forced to rewrite a cliché from the Ford Model T era and start telling customers they can have any color they want as long as it isn’t black.

Some darker hues will be available in place of black, but right now they are indentified internally at paint suppliers with names such as “mud-puddle brown” and are truly ugly substitutes for today’s rich ebony hues.

So buy a black car now, because soon they won’t be available or will look so putrid you won’t want one. And that’s too bad, because paint suppliers say black is the second- or third-most popular vehicle color around the world.

The problem stems from a new “cool paints” initiative from the California Air Resources Board. CARB wants to mandate the phase-in of heat-reflecting paints on vehicle exteriors beginning with the ’12 model year, with all colors meeting a 20% reflectivity requirement by the ’16 model year.

Because about 17 other states tend to follow California’s regulatory lead, as many as 40% of the vehicles sold in the U.S. could be impacted by the proposed directive, suppliers say.

The measure is aimed at reducing carbon-dioxide emissions and improving fuel economy by keeping vehicles cooler on sunny days and decreasing the amount of time drivers use their air conditioners.

The rationale goes like this: Vehicle AC units sap engine power and hurt fuel economy. If vehicle paint and glass reflect more heat, car interiors will be cooler. That means drivers will use their AC units less, the compressors won’t have to work as hard and auto makers will be able to use smaller AC units in the future.

Reflective coatings and glazing (glass) already have proven to save energy when used on buildings, and this legislation is based on architectural standards.

On the surface, it’s not a bad idea, but fundamental issues reveal profoundly flawed legislation: Buildings and vehicles are manufactured and recycled differently, and no one buys a building based on its color.

Another troublesome fact: Heat-reflecting paints for black and other dark colors on vehicles have not been invented yet.

Paint suppliers also say heat-reflecting pigments that could be used in automotive applications contain toxic heavy metals that cause environmental damage and create health and safety issues during manufacturing and recycling.

At least one auto maker estimates the additional cost of using these paints at $100 per car, not counting required changes to assembly plant painting systems, which could be significant.

So far, auto makers are holding their tongues on this subject, but automotive paint suppliers, such as PPG Industries, are tearing their hair out.

“PPG obviously has a very large architectural division that paints lots of buildings,” says Connie Poulsen, global director-product management, at PPG. “The theory when (CARB) started this was you take the pigments used in buildings and put them into car paints. That’s a good theory; unfortunately it doesn’t quite work that easily. Believe me, we tested it right away.”

“Requirements for color palettes are different, the process is different, the pigments used are different,” Poulsen says, adding that new automotive paint systems also have to undergo two years of rigorous testing before being approved for production. That’s yet another item government bureaucrats never considered – along with 3-year product lead times.

Some California rules are problematic because they are utopian and unworkable. This legislation is flat-out lazy. It’s a cut-and-paste job from the state building code that ignores smarter, more-effective automotive solutions already in production or on the way, such as more efficient AC units and solar-powered ventilation fans that work automatically when a car is parked in the sun.

Struggling auto makers and suppliers must not be forced to waste their limited resources on the cool paints initiative, an ill-informed wasteful boondoggle that embarrasses the environmental movement.