I-5 Smarter Highways signs in use with disabled semi in right lane

[RobertSeattle]

I've noticed that often the leftmost HOV lane is 5 or 10 MPH higher than the regular lanes. Why is that?

[doomsjay]

@RobertSeattle Staggered speed limits. In the left most lane, before entering downtown of course, drivers don't need to yield so much to vehicles entering and exiting the highway.