California Motor Vehicle Code 21655
High Occupancy Vehicle (HOV) Lanes
HOV lanes, diamond lanes, and car pool lanes are all the same thing. No matter what you call them locally, they all fall under vehicle code section 21655. This section makes it a crime to drive in the car pool lane without the required number of occupants.
Do not enter the car pool lane for any reason if you are not carrying the required number of passengers in your car or truck. The California Highway Patrol watches for this, and will give you a ticket if they catch you.
Car pool lanes are usually indicated by diamond symbols on the roadway, as well as signs setting the minimum number of occupants allowed in the vehicle. There will also be signs on the roadways letting drivers know the hours in which HOV lanes are restricted. In many cities the restrictions are in place 24 hours a day. In some less congested cities the restricted hours are only during peak times. Check with your local authorities if you are unsure what the rule is in your area.
Car pool lanes are designed to move more people with less congestion because they require fewer cars to be on the roads. This lessens stress levels for drivers forced to travel during the morning and evening rushes. It also lessens the amount of air pollution caused by fuel-consuming vehicles. If you are caught driving in a car pool lane during restricted hours you will probably be ticketed.
Busses, emergency vehicles, and motorcycles are allowed to drive in the designated car pool lanes, even during restricted hours. Most zero-emission vehicles are also allowed to drive in the carpool lanes. You must get the required sticker from the DMV to drive a single-occupant car in the HOV lane.
Never cross solid double yellow or white lines to enter a car pool lane. Double lines are an indication that the conditions are unsafe to enter the lane in that area. Wait until you are outside the double lines and back to where the lines are broken, before entering or exiting the car pool lane. If you are caught crossing the double yellow lines, you will receive the same ticket under CVC 21655.
Move out of the car pool lane if an emergency vehicle is approaching with lights and siren. Emergency vehicles always have the right-of-way no matter what lane you are driving in. Remember to move out of the car pool lane only when it is safe to do so.