Firstly:
Restricting this regulation to commercially operating vehicles already reveals disingenuous intentions of the authors of the law. Non-commercially operating vehicles, such as american pick-up trucks with grossly oversized engines, are idling in parking spaces all over California, at shopping malls, at Post-Offices, in campgrounds, etc It begs for the question: Do their drivers not love their children, to expose them to such massive amounts of carcinogenic diesel particles? Or are they just testosterone laden morons?

Secondly:
The extended exceptions to this regulation makes it nearly impossible to enforce. Are Californians so dull to let their lawmakers get away with such harmful absurdities? Or are they unable to understand the issue?

In the absence of such restrictions and exceptions, non-polluting or less polluting alternative heating/cooling equipments would suddenly become popular. Truck equipment such as electric air conditionner(heater and cooler) powered by a separate system of batteries and inverter is readily available as a kit. Equally available are separate, rather small but very efficient and reliable little diesel heaters such as Eberspaecher, Webasto etc.

CO2 is one of the most important causes of soo to be catastrophic Global Warming. But guess what, in California you can NOT buy the very low CO2 emitting cars such as VW diesel cars and the excellent new Jeep Liberty CRD, allegedly because "they do not meet California standards"... One can only conclude that Euro III and IV norms are perceived as pure balderdash by the sadly inept corps of California law-makers. Not to mention of the nearly total absence from the whole US market of the plethora of excellent diesel passenger vehicles and vans, whether Japanese or European makes. And for the record, outside the US, Chrysler mini vans, PT cruisers etc., Jeeps etc are offered with...diesel engines!