Reports say Toyota expects to sell as many as 15,000 of its 2012 Prius Plug-In Hybrid model per year in the United States.

But electric-car fans and advocates have vigorously debated whether the plug-in Prius is a "real" electric car, whether its 9 to 14 miles of electric range is adequate, and how much of an increase in gas mileage it delivers over the standard 50-mpg 2012 Prius hybrid.

None of that matters.

Toyota is likely to sell every single 2012 Prius Plug-In Hybrid it can deliver to California dealers for one simple reason.

It's about the stickers, stupid.

Put more politely, the 2012 Toyota Prius Plug-In Hybrid is expected to qualify for the highly prized Clean Air Vehicle sticker in California that gives its driver access to High-Occupancy Vehicle lanes on certain crowded freeways in and around San Francisco and Los Angeles even when traveling solo.

That privilege--formerly extended to 75,000 owners of three specific hybrids, but now ended for those cars--turned out to add as much as $1,500 in value to the value of those hybrids in the used-car market against the same cars without the stickers.

So it's logical to expect that the 2012 Prius Plug-In, with a base price starting at $32,760 including destination, will enjoy the same popularity.

Traffic congestion remains grim in the state's two largest urban agglomerations, and time is money.

Right now, the only new cars that qualify for the white Clean Air sticker are the electric Nissan Leaf (with a range limited to 100 miles or so), the Tesla Roadster (starting at $109,000), and the tiny numbers of natural-gas Honda Civics and hydrogen fuel-cell Honda FCX Clarity models.

Tesla Roadster with CA Clean Air Vehicle sticker -- flickr user jurvetson

Tesla Roadster with CA Clean Air Vehicle sticker -- flickr user jurvetson

So for drivers who are leery of the all-electric Leaf's limited range, but want solo driving in less-crowded HOV lanes, the Prius Plug-In is the easy, obvious, best-known solution.

And we predict there will be waiting lists for the car for many months as word gets out.

The one fly in the ointment? That would be plans by local transportation authorities to convert HOV lanes to tolled "Lexus lanes," in which drivers pay a variable fee for solo access to those same lanes.

Under those plans, electric-car drivers would pay the same tolls as any other solo driver--and they're not happy about it.

But for every other HOV lane in the crowded parts of California, expect to see lots and lots of Priuses starting next spring. They'll look just like regular 2012 Priuses, except for a second round door (for the charge port) on the right rear fender--and that invaluable green white carpool lane sticker on the bumper.

2011 Chevrolet Volt drive test, March 2011

2011 Chevrolet Volt drive test, March 2011

The 2012 Chevrolet Volt extended-range electric car does not qualify for California Advanced Technology-Partial Zero-Emission Vehicle (AT-PZEV) status, which would allow its drivers to get the same sticker--even though it runs electrically for up to 40 miles before the range-extending engine kicks in, unlike the Prius.

Although Chevy has said in the past it plans to qualify the Volt for the sticker, GM representatives refused to say when that would happen--or whether they would charge extra for AT-PZEV status in Volts destined for California and the other states that have adopted its emissions standards.

So who cares about plugging in? It's all about the sticker--even if Prius Plug-In drivers never once plug in their car.

Does that make sense to reduce emissions, which is the stated goal of the HOV access scheme? Oh, that's another story altogether.

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