While that is not exactly correct, for the most part it is true. You MUST have a special FasTrak Transponder to use the far left lanes as of November 10th, 2012. The Transponder can be set to 1, 2 or 3 or more folks, and if you have a transponder and a group, you will not be charges to use the lanes (though you might have to pay a small monthly rental fee for the transponder).
So if you are renting a car, more than likely you won't be able to access the lanes, unless the rental company offers a device, which they more than likely will charge a per day fee for.
You do NOT want to go into these specially marked lanes without a Transponder, as they will have special cameras designed to take pictures of license plates. The ticket goes to the registered owner of the car, and for rental companies, they have a clause in the contract that allows them to charge your credit card for the cost of the citation, which can reach $100's of dollars plus an administration fee.
The I-10 lanes are scheduled to convert early next year.
The I-405, I-5, 22 and 55 freeways special lanes are still "standard" Carpool lanes, where anyone can use them is they have 2 or more folks in the vehicle.