The American Council for an Energy-Efficient Economy (ACEEE) has suspended providing Green Scores for Volkswagen's diesel vehicles until further notice in the wake of the automaker's diesel scandal, the council announced.

ACEEE's Green Scores for Volkswagen's diesel vehicles "are no longer reasonable estimations of the environmental impact" of the vehicles, according to Shruti Vaidyanathan, senior transportation researcher at ACEEE.

"Volkswagen's diesel cars have performed well on ACEEE's annual rankings since 2009, hovering just below our list of the top twelve "Greenest" vehicles with Green Scores in the high 40s," Vaidyanathan wrote. "However, a 40-fold increase in on-road NOx would mean that these vehicles did not deserve those high Green Scores."

ACEEE's Green Score is a single measure that incorporates life-cycle greenhouse gas and criteria pollutant emissions, fuel cell vehicle analysis, and an estimate of nuclear damage costs. Green Scores of the 1,000-plus configurations of all 2015 model-year vehicles are available for free in the greenercars.org interactive database, along with each configuration’s fuel economy, health-related pollution impacts, and greenhouse gas emissions.

On Sept. 18, the EPA accused Audi and Volkswagen of using a software algorithm in its four-cylinder diesels to circumvent federal emissions standards. The cars from the 2009 to 2015 model years could detect when the car is undergoing official emissions testing and turn on full emissions controls only during that test. This would violate the Clean Air Act.

The allegations cover about 11 million models, such as the Jetta TDI (2009-2015), Jetta SportWagen (2009-2014), Beetle TDI (2012-2015), Golf TDI (2010-2015), Golf SportWagen (2015), Passat TDI (2012-2015), and Audi A3 TDI (2010-2015).