The Clean Vehicle Rebate Project offers graded purchase incentives for clean vehicles, on top of the federal tax credit of $7,500 (£5,200). It’s helped to make California the most advanced alternative drivetrain market in the United States, with over $291m (£201m) in rebates issued against 137,200 vehicles.

Under reforms effective from the 29th March, an additional $1,500 (£1,040) will be available for households with an income less than or equal to 300% of the federal poverty level – equating to $35,640 (£24,720) for an individual or $72,900 (£50,570) for a family of four.

This is on top of the graded rebates already available – fuel cell vehicles get a $5,000 (£3,470) rebate, dropping to $2,500 (£1,735) for electric vehicles, $1,500 (£1,040) for plug-in hybrids and $900 (£625) for electric bikes and other small vehicles. It means low income households could claim $11,500 (£7,980) off the price of an electric vehicle.

At the other end of the market, the highest earners will no longer receive state rebates against plug-in hybrid or electric vehicles. This applies to single earners with an income of over $250,000 (£173,420), $340,000 (£235,850) for household main earners, or $500,000 (£3,468,850) for joint tax filers. However, these will continue to be eligible for the $7,500 (£5,200) federal incentive, and the $5,000 (£3,470) rebate on fuel cell vehicles.

The Center for Sustainable Energy, which oversees the project for the California Air Resources Board, said additional incentives will be available for heavily polluted areas, including $15,000 (£10,400) for public agency fleets.