First they tried mandating white paint. Then they tried requiring black windows. But (surprise!) neither of these attempts to reduce CO2 emissions from vehicles passed public muster so the busybodies at California’s Air Resources Board (CARB) have (finally) scrapped their global-warming-fighting “cool cars” rule.

The cool-cars idea has been bouncing off guardrails for the last two years as part of California’s zealous attempt to reduce greenhouse-gas emissions from cars a full 30 percent by 2016 (with domino effects across the country, since California is the biggest U.S. car market).

When the CARB’s first attempt to reflect heat by regulating paint (essentially meaning you could have any color you wanted as long as it was white) was ditched out of fear of consumer backlash, its minions tried the backdoor by requiring manufacturers to make tinted windshields.

That strategy put activists on the more familiar ground — evil corporations are anti-green! But then the cops got involved. The California Police Chiefs Association, California State Sheriffs Association, and Crime Victims United of California echoed automaker concerns that mandated window-glazing would scramble signals from cell phone and ankle monitoring bracelets worn by felons.

“The ‘cool car’ technology threatens to undermine an already imperfect monitoring tool,” police chiefs warned at a time when the state wants to release more perps to alleviate prison overcrowding. In other words, the greens’ “public health threat” got trumped by “the public safety threat.”

But don’t expect CARB to go down easy. CARB spokesman Stanley Young says “instead, the board will pursue a performance-based approach as part of its vehicle climate change program.”

We can hardly wait.