California has long been a leader when it comes to encouraging the still maturing 'green car' industry, with all kinds of initiatives that encourage automakers to invest in cleaner technologies, or that help charging infrastructure be built, or simple that give incentives to buyers of vehicles that emit less pollution than traditional gas and diesel vehicles. But one thing has become apparent with one-size-fits-all incentives; the wealthy benefits disproportionally. It makes sense, since electric cars haven't yet reached the point of being affordable to all (especially Tesla's), but it's not the best way to use incentive dollars to encourage the industry to grow. A millionaire will probably buy a Tesla anyway, but a low income family might skip over a LEAF if they can't get a generous rebate.
To optimize that system, the California Air Resource Board (CARB) has made some change to take into account the income of people who are eligible for rebates.
The first change is that lower-income households will get a large boost in assistance. Those with incomes less than 300% of the Federal Poverty Limit will now get up to $3,000 toward a plug-in hybrid, $4,000 for an EV, and $6,500 for a fuel cell vehicle.
This means individuals earning less than $35,310 and a family of three earning less than $60,270 now qualify for double the old amount for plug-in hybrids and 60% more on EVs. Previously the rebates were $1,500 and $2,500 respectively. (source)
Here's a matrix that shows how the new system will work:
As you can see, if you are earning less than 300% of the federal poverty level, you get boosted rebates of $4,000 for a battery EV and $3,000 for a plug-in hybrid, but if you make more than $250k as an individual or $500k in joint filings, you are not eligible at all (to the chagrin of many Tesla buyers in California).
Also from CARB, here's a breakdown of rebates for greener vehicles in California so far, through April 2015:
As you can see, the usual suspects dominate: The Nissan LEAF, Tesla Model S, Chevrolet Volt, and Toyota Prius PHEV.
This last graph, also from CARB, shows monthly demand for EV and plug-in hybrid demand over the past three-and-a-half years. The trend is pretty clearly up, though there are bumps in the road.