The strict new regulations could threaten the popularity of such open-top staples as the Jeep Wrangler with the California Air Resources Board forcing manufacturers to install advanced glazing on glass - to keep air conditioning power use to a minium - and tinting glass sunroofs until they are "effectively black".
The rules also disallow flexible plastic windows, such as those used in Jeeps popular soft-top Wrangler models.
Hardtop variants of the Wrangler could also be made comply with the regulations, but those models account for comparatively small volumes in Jeep’s warmer climate markets.
“The very popular Jeep Wrangler fitted with a soft convertible top uses flexible roll-up side windows which are not capable of meeting the side window standard,” Mr Ross Good, Chrysler’s senior manager of government relations told CARB.“Outlawing the soft top would require us to use the hard-top vehicle with the hard windows, which would add significant weight to the vehicle.”
The proposed regulations are set to take affect from 2012, although there is a “roll-in” period before the strictest requirements arrive in 2016. Beginning in just two model years, vehicle windows would need to be capable of preventing 45 per cent of the sun’s energy from entering the cabin. That requirement would jump to 60 per cent by 2016.
Although the regulations are yet to be finalised, CARB hopes to publish its completed regulation by the end of this month. The public will be given a 15 day comment period before the final laws are set by next May.
The glazing also affects GPS and mobile phone signals with phone carriers saying “more time was needed to assess the impact”. In an interesting twist, ankle bracelets - as used on parolees - “may be adversely affected by the metallic reflective standard.”
CARB is adamant about the benefits of the new standard despite the costs added to vehicles, which the board says would be recuperated in five to 12 years of normal driving.
“This is a common sense and cost-effective measure that will help cool the cars we drive and fight global warning,” said Ms Mary Nichols, CARB chairwoman.