Yes. The HOV lanes are meant to reduce the number of cars on the road by encouraging ride sharing. At fiirst I thought it was to prevent traffic congestion and improve driving time, but the sole purpose from the beginning was to get more people into fewer cars to reduce pollution/emissions. If you have plates that are registered before July 2006 you can ride HOV-3; anything registered after that date you are limited to HOV-2. When the law was being passed with the hybrids, everyone south of DC down the I-95 corridor went out and bought hybrids which quickly clogged the HOV-3 lanes with individual drivers!