Frequently Asked Questions
Carpool Lane
- What cars can use the carpool lane with one passenger?
- Are carpool stickers for hybrids still available?
Plug-in Vehicles and Charging: Visit our new Plug-in Vehicle Resource Center 
- How do I set up my home to charge my EV?
- At what "level" do I need to charge my EV?
- Will a home charger come with the EV I buy?
- Can I sell back electricity from my EV battery through vehicle-to-grid technology?
- How does paying for kilowatt hours compare to buying gasoline?
- How much will my monthly electric bill go up?
- Will electric cars strain the electrical grid?
Vehicle Emissions
- How can I reduce my car's smog emissions?
- How can I reduce my car’s greenhouse gas emissions?
- When I'm at the dealership, how can I tell which cars are cleanest?
- How much does the average new car pollute?
- How can I find out how much the car I’m driving now pollutes?
- What happened to the pollution terms we used to hear, like ZEV, AT PZEV, PZEV, SULEV, ULEV, and LEV?
Environmental Performance Label Scores
- What is the Environmental Performance Label?
- What is a Smog Score?
- What is a Global Warming Score?
- What is the difference between the Smog and Global Warming Scores? Is one more important than the other?
- How does fuel economy factor into scores?
- Why can the same make and model car have different scores?
- About how much more does a car pollute if the Smog or Global Warming Score is just one digit lower? For instance, is a 6 really a lot dirtier than a 7?
- Why aren’t there Global Warming Scores for older vehicles?
- How can I find out what scores the car I’m driving now would get?
- Why worry about comparing Smog and Global Warming Scores when ALL new vehicles have gotten much cleaner?
Vehicle Technologies & Performance
- How well do clean technology cars perform? And are they available in different sizes?
- Is a NEV a viable option for me?
- Is a CNG vehicle a good option for me? Where and how would I refuel a CNG car?
- Are ethanol cars good for the environment?
- Are diesel cars coming back?
- Is using biodiesel in a diesel car good for the environment?
- Can I still buy an electric vehicle?
Incentives & Vehicle Cost
- What types of vehicles qualify for incentives?
- How much does it cost to replace the battery in a hybrid car?
What cars can use the carpool lane with one passenger?
California law allows single-occupant use of High Occupancy Vehicle (HOVs) lanes by qualifying clean alternative fuel vehicles. Use of these lanes with only one occupant requires a Clean Air Vehicle Sticker issued by the California Department of Motor Vehicles. Only white Clean Air Vehicle stickers are still being issued, and they are available for zero emission vehicles (100% battery electric or hydrogen fuel cells) and CNG vehicles. Hybrid vehicles are no longer eligible for HOV lane stickers, and hybrids with existing (yellow) stickers will expire on December 31, 2010.
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What is the Environmental Performance Label?
The Environmental Performance (EP) Label is required by the California Air Resources Board to be displayed on every new car, starting with the 2009 model year. The EP Label is a rating system that ranks a vehicle's impact on smog and global warming. Two scores, from 1-10 are provided on the EP Label – one for smog emissions and one for global warming emissions. The HIGHER the scores, the cleaner the vehicle is. Learn More >
What is a Smog Score?
The Smog Score ranks each vehicle's pollutant levels of Non-Methane Organic Gases (NMOG) and Oxides of Nitrogen (NOx) on a scale of 1-10 relative to all other vehicles within the current model year. The HIGHER the score, the cleaner the vehicle. Learn More >
How can I reduce my car's smog emissions?
There are several things you can do to reduce the smog emissions from the car you are driving now. Learn More >
What is a Global Warming Score?
Beginning in 2009 in California, all new vehicles are required to display a Global Warming Score found on the new Environmental Performance Label. The Global Warming Score ranks each vehicle's greenhouse gas emissions, including carbon dioxide (CO2), methane (CH4), nitrous oxide (NO2), and hydroflurocarbons (HFCs) from air conditioner refrigerant. The ranking is on a scale of 1-10 relative to all other vehicles within the current model year. The HIGHER the score, the cleaner the vehicle is. Learn More >
How can I reduce my car’s greenhouse gas emissions?
Any time you are using less gasoline, you are releasing fewer greenhouse gases into the atmosphere and therefore, reducing the major contributor to global warming. There are several ways you can reduce your current vehicle's impact on global warming. Learn More >
What is the difference between the Smog and Global Warming Scores? Is one more important than the other?
The short answer is that they are caused by different pollutants, and have different effects on the environment. But, both types of emissions are equally important to reduce.
The Smog Score corresponds to the amount of smog-forming emissions from a car. These emissions consist of Non-Methane Organic Gases (NMOG) and Oxides of Nitrogen (NOx) and cause more localized, immediate pollution and cause respiratory health problems, can inhibit plant growth and can cause damage to crops and forests.
Whereas, the Global Warming Score is associated with the amount of greenhouse gas emissions or carbon dioxide equivalent released for a car. Greenhouse gas emissions are the chief contributors to global warming, causing a more collective disruption of climate stability, such as warmer oceans, greater temperature extremes, and altered wind patterns.
When choosing a new car and comparing Smog and Global Warming Scores, it's a good idea to take both into consideration. Comparing vehicles with a combined score in mind is a good way to determine the overall environmetnal effect. Learn More >
How does fuel economy factor into scores?
A car with a higher Global Warming Score will typically burn less fuel. Buying a hybrid is one option for improving fuel economy as well as reducing smog-forming emissions. There are a great variety of models to choose from today, and more are coming to market every year.
Search the variety of hybrids now.
Why can the same make and model car have different scores?
Two cars may look identical, but their engines could be very different. Auto manufacturers certify their vehicles by their engines, which are given engine family numbers. For example, a vehicle with a manual transmission could have a different engine family number and pollute much more than the same car with an automatic transmission. Different technologies can also have a range in greenhouse gas and smog emissions. For instance, not all hybrids have reduced smog emissions. The best way to make sure you are buying the cleanest version of the new car you want is to look at the Environmental Performance Label.
If buying an older car, you can find the engine family number posted on the Vehicle Emissions Control Information label found underneath the hood. Then, look up that number on the engine family search and find out the Smog Score. The higher the score, the cleaner the vehicle.
Using Smog Scores is the only way the environmental impact of older vehicles can be compared, since Global Warming Scores only became available in 2009 model year vehicles and beyond. Learn More >
When I'm at the dealership, how can I tell which cars are cleanest?
Starting with the 2009 model year, that distinction is very easy. The Environmental Performance Label rates each car's Smog and Global Warming emissions and gives a score for each. The higher the score, the cleaner the vehicle. You can compare scores right here before you go to the dealership by visiting the Vehicle Search.
About how much more does a car pollute if the Smog or Global Warming Score is just one digit lower? For instance, is a 6 really a lot dirtier than a 7?
When looking at the Environmental Performance Label the difference in Global Warming emissions between, say a score of a 6 and a 7 can be as much as 80 grams of carbon dioxide (CO2) per mile. So, if you drive 20,000 miles per year, you're putting more than 35,000 more pounds of CO2 into the air with a score of 6 than you would if you bought a 7.
For smog, under the same scenario, a car with a score of 6 will put an additional one pound of Non-methane organic gases (NMOG), oxides of nitrogen (NOx) and other pollutants into the air every year when compared to a 7.
Why aren’t there Global Warming Scores for older vehicles?
The requirement for Global Warming Scores to be posted on vehicles didn’t come until the passage of Assembly Bill 1229 in 2005. AB 1229 required the California Air Resources Board (ARB) to redesign the Smog Index Label that had been appearing on vehicles since 1998. The redesign of the Smog Index Label resulted in a new label, called the Environmental Performance Label, that includes two separate scores – one for Smog emissions and another for Global Warming emissions. The Environmental Performance Label is required to be affixed to the window of every new vehicle beginning with the 2009 model year. The higher the score, the cleaner the vehicle.
How can I find out what scores the car I’m driving now would get?
If you have a 2000 model year vehicle or newer, you can search and compare your car's annual smog emissions using the Compare Your Car tool.
Using Smog Scores is the only way the environmental impact of older vehicles can be compared, since Global Warming Scores only became available for 2009 model year vehicles and beyond.
How much does the average new car pollute?
The average new vehicle scores a 5 in both Smog and Global Warming on the Environmental Performance Label.
For Global Warming, a score of 5 means the impact is between 360 and 399 grams per equivalent mile of carbon dioxide (CO2), methane (CH4), nitrous oxide (N20) and emissions related to the use of air conditioning.
For Smog, a score of 5 means the impact is 0.125 grams per mile of Non-Methane Organic Gases (NMOG) and Oxides of Nitrogen (NOx).
Any car that has a Smog or Global Warming Score higher than 5 is cleaner than the average vehicle. The higher the score, the cleaner the vehicle.
Learn more about pollutant amounts for each score on the California Air Resources Board web site.
Why worry about comparing Smog and Global Warming Scores when ALL new vehicles have gotten much cleaner?
Cars have certainly gotten much cleaner over time, however motor vehicles are still a big contributor to smog and global warming. This is because there continues to be a growing number of cars on California's roads driving more miles every year. Right now Californians drive 825 million miles every day – producing 5.4 million tons of smog forming pollutants daily.
With the introduction of the Environmental Performance Label in 2009, it is easy to compare emissions of vehicles and choose something cleaner. Buying vehicles with HIGH Smog and Global Warming Scores makes a tremendous difference in how much we pollute.
How well do clean technology cars perform? And are they available in different sizes?
There are a variety of new technologies that have been in the spotlight the last few years, and many have come to market in large numbers. Battery electric, hybrid electric, compressed natural gas (CNG), ethanol (E85) flex fuel, clean diesel and cleaner gasoline vehicles are all available to consumers in a range of makes and models. Hydrogen vehicles and plug-in hybrid electric cars are on the horizon and will be coming to showrooms soon.
The way these vehicles perform will vary between make and model just as traditional vehicles do. Clean technology vehicles are comparable in power, style, luxury and amenities to traditional gasoline vehicles. And, they have an added bonus of reduced emissions, and usually better warranties and some really great tax incentives. Learn More >
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Is a NEV a viable option for me?
A neighborhood electric vehicle, or "NEV" is a battery electric vehicle that is zero emission, and a great choice for local, low speed transportation. People who drive regularly on streets with speed limits of 35 miles per hour or less, and need to go less than 30 miles on a charge are good candidates for a NEV. NEVs typically have a top speed of 25 miles per hour and are easily charged in a 110-volt outlet.
Search for NEVs.
Is a CNG vehicle a good option for me? Where and how would I refuel a CNG car?
A compressed natural gas (CNG) vehicle is a great option for many people. They have all the capabilities of gasoline vehicles, with much less pollution and the ability to drive in the carpool lane with just one passenger in California (and some other states). CNG vehicles are also very similar to gasoline vehicles in the method and time it takes to fuel, and have comparable driving range. It’s easy to find fueling stations as well, with more than 200 already in California.
Learn more about CNG vehicles and find fueling stations at the California Natural Gas Vehicle Coalition web site.
Search for CNG vehicles.
Are ethanol cars good for the environment?
This really depends on how the ethanol, or “E85” is made. Typically, they have similar smog-forming emissions and fewer global warming emissions. Also, since the fuel is produced domestically, it helps to reduce our dependence on foreign oil. Learn More >
Search for E85 vehicles.
Are diesel cars coming back?
Growing numbers of "clean diesels" are coming to market, offering improved fuel economy and reduced greenhouse gas emissions compared to gasoline vehicles. While diesels still have room to improve when it comes to smog emissions, they are expected to meet more stringent emission standards over the next few years. Learn More >
Search for diesels.
Is using biodiesel in a diesel car good for the environment?
It depends. Emissions of oxides of nitrogen can increase with the use of biodiesel in a conventional diesel engine. Biodiesel blended with conventional petroleum derived diesel at concentrations up to 20 percent (B20) is currently used in some diesel engines. Using either blended or pure biodiesel in a diesel (compression ignition) engine will reduce emissions of unburned hydrocarbons, carbon monoxide, sulfates, and particulate matter.
Since the feedstock for biodiesel can be domestically produced, it reduces the nation's dependence of foreign oil. Learn More >
How much does it cost to replace the battery in a hybrid car?
Since hybrids are relatively new to the market, actual battery replacement costs are generally unknown. However, it is projected that a new battery pack will likely fall in the $2,000 or so range when aging hybrids get to the point where replacement is needed.
Are carpool stickers for hybrids still available?
Yellow Clean Air Vehicle Stickers were limited to the first 85,000 applicants of qualifying hybrids. This limit has been reached and there will be no more yellow stickers issued. Yellow stickers issued to date are set to expire on December 31, 2010, however, pending legislation (SB 535) may extend the use of existing yellow stickers until July 1, 2011.
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How can I find out how much the car I’m driving now pollutes?
If you have a 2000 model year or newer vehicle, you can search and compare your car's Smog Scores in the Compare your Car section.
What happened the terms we used to hear when it came to clean cars, like ZEV, AT PZEV, PZEV, SULEV, ULEV, and LEV?
These terms are the California Air Resources Board’s (ARB) emission standards that are still used in California's motor vehicle regulations. However, a simpler way has been created for consumers to find the cleanest cars – the new Environmental Performance Label. These emission standards now correspond to a Smog Score found on the Environmental Performance Label.
Can I still buy an electric vehicle?
Yes. Electric vehicles are available for purchase now as full size and neighborhood EVs (NEVs). More models are expected to come to market in the next couple of years, giving consumers a greater variety to choose from.
Search battery electric vehicles.
Search neighborhood battery electric vehicles.
Learn more about hydrogen fuel cells.
What types of vehicles qualify for incentive money?
Incentives are available for many hybrids and alternative fuel vehicles – from rebates, discounts and tax breaks to free parking and HOV lane perks. Learn More >
How do I set up my home to charge my EV?
If you are thinking of installing an electric vehicle charger at your home, there are a few important contacts to make. Your local electric utility will help you determine your charging needs and set you up with the proper electricity rate structure. Your local building and safety department should be able to tell you whether any permits will be required. And, the manufacturer of your EV will be able to guide you through the general process and the charging equipment you will need for your vehicle. Learn More >
At what "level" do I need to charge my EV?
Most EVs will charge at home on one of two charging "levels". Depending upon which charging level you select, you may need to upgrade your home electrical system. A plug-in hybrid or neighborhood EV may only require level 1 charging, which is done on a standard 120-volt outlet that typically won't require modifications to your electrical panel or home wiring. Most PHEVs will take four to six hours to charge at level 1. Full size battery electric vehicles will need to charge at level 2, which is done on a 240-volt rated charging unit. Most BEVs will take three to six hours to fully charge at level 2. Learn More >
Will a home charger come with the EV I buy?
EV buyers will likely need to pay for charging equipment and installation in addition to the cost of the vehicle. For EVs requiring level 2 charging the cost could be between $2,000 and $4,000, but with tax and other incentives you could end up paying a lot less than that (and don't forget there are additional incentives for the purchase of the EV as well). Vehicle manufacturers typically help EV buyers coordinate their charging needs through arrangements with specific EV charging equipment manufacturers. Nissan, for instance, has partnered with Aero Vironment to install chargers for the Leaf, however, customers are free to cost compare and use their own licensed electricians for the installation if they desire. Learn More >
Can I sell back electricity from my EV battery through vehicle-to-grid technology?
No, this technology is not currently available. Automakers and utilities are currently investigating plug-in vehicle-to-home and vehicle-to-grid technologies. These technologies would enable EV owners to use their vehicles as a source of electricity during a power outage or emergency, and it would enable customers to offer electricity back to the grid during periods of high electricity demand.
How does paying for kilowatt hours compare to buying gasoline?
According to the Electric Power Research Institute (EPRI), plug-in hybrid electric vehicles operate at the equivalent of 75 ¢ per gallon of gasoline.
How much will my monthly electric bill go up?
The incremental cost for charging an electric vehicle is different for everyone. The size of the increase will depend on the type of electric vehicle you buy, the type and size of battery it uses, your electricity rate plan, current monthly electrical use, and the amount that you drive.
Will electric cars strain the electrical grid?
There is more than enough excess capacity to charge a significant number of EVs, but we do need to make sure charging is properly managed. EVs can pull an amount of electricity comparable to what a typical home requires when it's hot and the air conditioner is working really hard. This could be a potential stress on transformers in neighborhoods with multiple EVs. When given adequate notice, utilities can accomodate additional electricity demand for EVs just as they would for hot-tubs, swimming pools and air conditioners. Charging when overall electricity demand is low, off-peak hours such as nights and weekends, helps manage demand while keeping electricity costs low for EV owners. And fortunately for EVs, these are the times when vehicles are typically sitting for long periods anyway, and therefore, the most convenient times to recharge.