The US western state of Colorado has reached an agreement with automakers to adopt California’s zero emissions vehicles plan, which has seen the latter state account for half of all electric vehicles on US roads.

Starting in 2023, Colorado will allow carmakers to earn credits for electric cars sold from 2021 onwards, according to the deal struck with the Auto Alliance which includes GM, Toyota, Hyundai and Volkswagen AG.

Following the lead of California, which now has over 600,000 electric vehicles registered out of the entire US fleet of 1.2 million, the state of Colorado will “provide the support Coloradans need to buy electric vehicles while allowing auto manufacturers to transition into Colorado’s ZEV program,” according to a statement released by the alliance.

“This agreement will ensure that Coloradans have access to the range of clean car choices that are increasingly available to consumers in other states,” said Colorado Transportation Department Executive Director Shoshana Lew in a statement to the press.

The agreement, which is due to be filed at the Colorado Air Quality Control Commission’s August hearing, includes battery electric vehicles (BEV) and plug-in hybrid electric vehicles (PHEV) that can drive at least 32km on pure electric power.

“Automakers are building more electric models while Colorado is investing in market conditions that encourage consumers to buy them, so we have developed a way to work together on our shared goal of getting more electric vehicles on Colorado roads,” the allinace said in an issued statement.

“We are extremely appreciative that the Polis administration worked with automakers and other stakeholders to find an innovative alternative regulatory proposal that will implement the ZEV program in Colorado

“All of this was made possible by the fact that Colorado has one of the highest adoption rates of electric vehicles in the country as well as the largest electric vehicle incentives for consumers to buy or lease a ZEV.”

According to data from Kelley Blue Book, an average of 14.6 electric vehicles are sold in the state on any given business day, and ranks 4th in the nation for EV sales – about 1.5% of the state’s cars are electric which is above the national average of 1.2%.

However, this is still far behind California, where EVs account for 4.7 per cent.