In most big cities, in the US, you will find, what we call, HOV lanes. They are usually on the left hand side on the freeway/highway, they are speed lanes for cars with 2 or more people. They were made for people to stop driving to work alone and car pool. Rules vary per state, so below is a little Q&A about HOV lanes.
When are HOV lanes used?
HOVs are usually between 6-9am and 3-7pm, although in LA, correct me if I'm wrong, but I think I saw a sign that it was 24hrs. What does that mean? It means that during these hours you are not allowed to be on it. And in LA, come on, the worse traffic I've seen in the US, I can understand that the HOV are24hrs.
What happens outside those hours?
You can drive on it for as long as you'd like.
What happens if you drive on a HOV lane alone in the car by yourself?
If you get caught by the police, you get a fine. Around $350-$450 + court fees.
Besides vehicles with 2+ people, who else can use HOV lanes?
Motorcycles, hybrid cars, buses, emergency vehicles.
How do I know I'm on a HOV lane?
They are marked by a diamond and divided from regular lanes, by a very thick white line or 2 white lines (like the one on the picture above)
Do you want to read a funny story? I have a friend who had a car with a very dark tint on the window. He's very smart, so he used the HOV lane because no one could see in, but one day, he got stopped by the police because his tinted windows were really dark, which he didn't know, and then he got in double trouble. Oh well... it was due.
Point of the story? DON'T DO IT!!
note - 1) I was stuck in traffic, so car not moving on the pics above. It was around 1:30pm because that's when I leave work, so I use the HOV lanes all the time ;-)