HOV, High Occupanacy Lanes are restricted to cars with only 1 driver. Most HOV lanes here in British Columbia must have 2 or more persons be be able to drive in them. Most HOV lanes allow single occupant motorcycles, but not all. It's very confusing but signs are posted on every highway as to number of persons or whether you require 2+ persons, or in some cases, more. You cannot just assume that you will be good with only 2 persons.
I have not paid attention to the line marking on the HOV lanes in the Seattle area but if I am not mistaken, they are all dotted. I only say this because if they were solid then I would be thinking twice about going into and out of them so freely.
On my commute to work I have a choice of a few different routes. Some routes are fast, another faster, and a couple are slow or slower. When I take the freeway I used to take the HOV lanes but found myself getting carried away, and I don't like the tail-gating vehicles behind me. You are in severe danger if you choose to ONLY go the posted speed and I don't find it very relaxing to go much over in this heavy rush hour traffic with people constantly jockying for position trying to get ahead. Most often I just daudle along in the slow lane. I would rather have the idiots in front of me, rather than directly behind.
So in response to Gary's (Mr H-D, UK) (<-- link) original question, I put caution aside and took the HOV lanes on the way home from work last week. Our HOV lanes are the left most lanes identified with a DIAMOND symbol. It is separated from the other regular lanes with either a dotted or solid line. The speed of the traffic that normally use these lanes are not normally travelling at the posted speeds. Aggressive drivers often approach very fast from behind and when confronted, they switchlanes back and forth without regard to the lines. Not so much on this day, but more so when traffic is less dense.
So to Gary, these dotted and solid lines are for you . . .
Thanks from the Pink Stig of BC