California had been pushing for stricter emissions standards
US President Barack Obama has announced tough targets for new fuel-efficient vehicles in order to cut pollution and lower dependence on oil imports.
The single nationwide standard aims to replace overlapping rules on emissions and efficiency set by federal agencies and states.
US carmakers and environmental groups have expressed support for the move.
Motorists in the US have been sending their views on the plans. Here is a selection of their emails.
SUPPORTING THE PLANS
I applaud President Obama's plans. I drive a hybrid that averages 40 miles per gallon. I think the US car manufacturers spent too many years ignoring both fuel efficiency and emissions improvement technologies in order to make profit - this was a bad decision. I have long wished that the US could match or even exceed European and Asian efficiency levels.
Margaret Driscoll, Camarillo, CA
I am thankful! It is about time in the US that we got out of the stone age and got our standards higher. We've had the technology for decades, so let us get our cars up to par with the rest of the world. With old man Bush no longer in office, let's reduce our dependence on foreign oil and start thinking seriously about our planet.
Austin, North Carolina
Even though it means I will have a lot of trouble buying a car in a few years, I am glad about these new targets for the sake of the environment. I also hope that the increased expense of driving will encourage cities to improve their public transport systems, and America to revive the use of regional trains.
This law should have been more aggressive. The US car market in 2016 will be barely catching up with the current efficiency of foreign vehicles, such as Toyota and Honda. How are the US car makers going to catch up in sales when their seven-years goal is short of what foreign car makers are doing already. If they don't reach at least 40, even 50 miles per gallon, they might as well close for business now and not waste tax payers money.
Churk Leung, Boston
I think it is a good start, although long overdue, but the standards need to be raised higher. I also think there should be a higher tax on four wheel drive vehicles. They are wasteful.
Matthew Range, Lantana, TX
Even though I am a graduate student relying on a stipend, I feel elated and I am more than willing to pay extra for a change as dramatic as this one. It is a shame that we needed a law to enforce something we should have done on our own - but having a leader do this for us is amazing.
Justin Y., NC
OPPOSING THE PLANS
There seems to be a fault in President Obama's plans. Carbon dioxide is a result of burning a carbon based fuel and so reducing it will encourage the production of smaller cars, but not necessarily greater engine efficiency. If efficiency is accomplished by using an electric battery, that will simply shift the pollution problem somewhere else.
William Cohen, Evanston
I believe President Obama's plan is a wonderful way to limit competition, increase the size of the federal government and carry on the myth of global warming. The president and his new "car czar" will gain control of the major car companies through lending from the Fed, quash the development of smaller car companies through regulation, and subject the people to driving small cars proven unsafe in crash tests all the while continuing to purchase foreign oil instead of developing new, clean energy sources.
Walker Stemmons, New York
What the auto manufacturers will do to meet federal emissions standards will be to make these new cars small and unsafe. I drive a big car with a big engine. It does 30 miles per gallon. It also has a five - star crash rating. I would not give up even one of those stars to gain fuel economy. However, if the car makers can find ways to increase efficiency without decreasing safety, I'd say, "Rock On!"
Paul Ethridge, Nebraska
I am a US motorist and I don't think much of Obama's plans. The Climate has been changing since there was a climate, and will continue to do so in spite of any human efforts. Raising the fuel efficiency is a laudable goal but there are fundamental problems in this approach. We will be driving lighter, underpowered cars, which raises safety concerns - less mass means more damage. Trucks will not be able to transport as much weight of goods, so it will take more trucks to move less goods. Let us not forget that global warming is an unproven theory, which has not been established as fact.
Michael P. Koryciak, Flint, Michigan