How Can I Tell?
Every car will be equipped with an emissions tag, which will tell you if the vehicle is federal or California emissions. Federal emissions stickers will just say, "This vehicle conforms to U.S. EPA regulations". California emissions vehicles will state, "This vehicicle conforms to U.S. EPA and State of California regulations".
Where Can I Find the Emissions Tag?
On light-duty vehicle and trucks, the sticker will be located under the hood or in the engine compartment.
Motorcycles will have the label in an easily-accessible location, such as under the seat, on the frame, or in the glove box.
Heavy-duty vehicles will have the tag on the engine block.