New cars sold in California must include windshields that block or absorb the sun's rays beginning in 2012, the state's Air Resources Board recently ruled.
The new regulation is meant to keep cars cooler, cutting the need for air conditioning, saving energy and reducing emissions that contribute to global warming, the agency says.
To meet the new rules, car windows will have to block 33 percent more of the sun's heat-producing rays than cars windows do today. Because the rays being blocked are in the infrared part of the spectrum, the windows would not require tinting, and will look no different from present-day car windows, said air board spokesman Stanley Young.
"It uses a very microscopic sputtering of metal particles that act as tiny invisible mirrors," Young said.
With more of the sun's heat blocked, cars interiors should be about 14 degrees cooler, SUV or pickup interiors about 12 degrees.
The reduction in use of air conditioning is expected to cut carbon dioxide emissions by 700,000 metric tons by 2020 -- the equivalent of taking 140,000 vehicles off the road for a year, the agency says.
The two-step regulation requires cars sold for the first three years to block 45 percent of the sun's heat-producing energy, windshields at least 50 percent; in 2016, car windows must block 60 percent.
The agency says it will cost an average of $70 for the first three years to comply, and $250 after 2016.
It's one of several measures adopted by the agency to cut greenhouse gas emissions, including a low-carbon fuel standard and a requirement that smog-check and other maintenance facilities check tire pressure.
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