There was a thread about someone who got a ticket pulling a boat in the hammer lane last week. Just some info, I saw the sign on I5 going south right across from the weigh station in Dupont that states something like
Autos with trailers or over 10,000 GVW prohibited in left lane. So, it looks like no matter what your GVW is you cannot be in the left lane for passing or any other reason if you are pulling a trailer. I didn't know this either, maybe a Thurston county thing? I don't know how far south this applies, or how far north, but it seems I5 is pretty picky about trailers!

Watch out for Mr. Bear, he is everywhere down here!

Actually it is a state law. Last year on the way home from fishing for gators, I got pulled over also but no ticket. I started a thread here, and this is what I found out.

Any vehicle in combination -- pulling a trailer -- must obey the posted truck speed limit. Also, any vehicle in combination may not use the far left lane for any reason (even to pass) on a three lane highway.

However, if the highway is two lanes, you can use the left lane. Also, if the highway is three lanes, and the third lane is a carpool lane, you CAN use the carpool lane if you have enough passengers. The carpool lane does not count as a third lane.

What I do not know, however, is if the highway is four lanes, and the fourth is a carpool lane, whether or not you can use the carpool lane. Since you cannot use the third far left lane, how can you get to the carpool lane?

You need a law degree to understand Washington's driving laws!!

Beam me over there Scotty.

Psc:
You're pretty much right on, except it's a fed law, and trucks & combinations may use the 2 right lanes, only. Hill climbing lanes, exit ramps, HOV lanes, etc...dont count. (Dont get caught in a HOV lane in a big rig, though.)
I dont believe Thurston Co is trying to get away w/ anything, though, there are localized restrictions which may be applied wherever DOT feels a specific need. So that RH lane thing is only for (probably) that particular hill grade.
The one thing very important, however, is that little combos are restricted to the truck & trailer speed limit... I see soo many cars w/ boats & campers zipping along at 70,(+ often) not even realizing its worth a real fat tix., and not aware of the public hazard they're bringing to the road... They dont realize how much more stopping distance they need, or how quick they can lose it if they blow a tire, or whatever.
I drove over the road big rig for as coupla years, and even tho I dont do it any more, the education I got was immeasurable. I saw some really stupid stuff out there, and was constantly amazed at how unwilling people were to accept responsibility for their lack of judgement...
Well, nuff said. Be safe getting there and back. Even if there are fish there to be caught, its just not worth a tix or accident.
'Head hunter

Thanks for the public service announcement. I wasn't aware that trailer vehicles had to travel at the slower speed. Will set the cruise contol accordingly.

Last year I was coming back from Lake Washington Sockeye Fishing, and I was cruising in the center lane as fast as the flow of traffic when a vehicle 2 cars up dynamited their brakes. To avoid the mess, i went out into the fast lane, and sure enough one of Washington's finest patrolman saw me, pulled me over, and gave me a ticket for $85. He did not give a Rat's butt about me trying to avoid the pile up.