You have no idea how many times somebody has decided to slow down in the carpool lane while the mainline is moving at full speed. Myself, as well as many people I know have simply broken the law and crossed the double yellow just to get ahead. It can get really stressful when you are trying to get somewhere before a certain time. Either they allow free-flowing entrance and exit in the carpool lane, or they establish a minimum speed limit in the carpool lane. There are people that think the carpool lane is a place to cruise and it is not. Now, low tolls are ok, but extremely high tolls, as they will be getting to soon on the South Bay Expressway (which isn't used as much as predicted), are just too unreasonable to be worth it. Not only that, the amount of toll roads in California isn't anywhere near the amount of toll roads on the East Coast, where there are toll roads that are very long. Based on that alone, it can be said the concept hasn't really caught on as much. HOT lanes and toll roads are great ideas that can work in California, but the prices shouldn't be allowed to skyrocket as they have with some private operators.