California has committed itself to adopting a slew of stringent automotive emission regulations.

Regulators in the American state voted unanimously on Friday to tighten the rules governing emissions, in a sign that the US is moving towards a new era of strict clean air rules.

The new regulations dictate that exhausts from cars and light trucks must be reduced by 25 per cent, with bigger trucks and SUVs required to slash emissions by 18 per cent.

A target date of 2009 has been set for the introduction of cleaner automotive technology, with all vehicles expected to meet the new air standards by 2016.

The move by the California Air Resources Board is being seen as a litmus test for the development of clean air regulations in the US, attracting criticism from some who argue that the state has no authority to impose such rules.

Other critics argue that the cost of developing new technologies will prove damaging for the industry and that the automotive sector does not yet have the capacity to deliver fully commercial clean air vehicles.

Nevertheless, with a number of high-profile supporters on board and the backing of Governor Arnold Schwarzenegger, Californian officials say they are confident of developing and implementing the clean air emissions.