While the recreational use of marijuana is legal in California, there are still restrictions on where it can be used. For example, the consumption of cannabis products, whether through smoking, ingesting, drinking, or vaping, is not legal in public places.
When it comes to smoking marijuana in a car, California law prohibits any type of marijuana consumption in a vehicle when it is in motion. This law applies to both drivers and passengers.
If your car is parked, then you can smoke marijuana only if (1) your vehicle is parked on private property and (2) you are not going to be driving. In other words, if you go outside of your home and smoke weed in your car that is parked on your private driveway, you will not be charged with a crime. However, if your car is parked on the street — or if you drive after smoking marijuana — then you could be charged with smoking marijuana in public or DUI of marijuana.