I blame The Eagles. By popularizing the meme of "fast lane" in preference to that of "passing lane", they've badly damaged the laminar flow of highways, and likely contributed significantly to road rage.

It is the fast lane in California. According to the California Driver Handbook, the left lane is known as the "fast" lane (p32). They suggest if there are three lanes to use the left lane to drive faster, pass, or turn left. They also say "Do not drive slowly in the left (fast) lane." (p64)

http://www.dmv.ca.gov/pubs/dl600.pdf

The California fast-vs-passing lane pattern also emerges due to two things that California requires that other US states tend not to require: semi-trucks must go slower and keep right.

From the handbook cited above, or see also signage on many CA highways: The maximum speed limit on most California highways is 65 mph. You may drive 70 mph where posted. Unless otherwise posted, the maximum speed limit is 55 mph on two-lane undivided highways and for vehicles towing trailers.

... When you tow a vehicle or trailer, or drive a bus or three or more axle truck, you must drive in the right hand lane or in a lane specially marked for slower vehicles. [emphases added]

On divided highways of 2 or 3 lanes in each direction, such as I-5 in the Central Valley, these requirements strongly separate traffic into 2 sets - semi-trucks doing 55-ish in the right lane, and non-trucks doing 65-70-ish in the "fast" lane. (okay, yes, 85-ish, except in Kern County).

The results are that 1) over-the-road truckers dislike driving in CA, and 2) CA non-truck drivers quickly learn to avoid the right lane.

The other 49 US states tend to have more of a "keep right except to pass" pattern, depending of course on other local variations, especially population density, traffic volume, and similar.

Source: someone who drives (and tows) in 18+ states per year.

> I wish more drivers would follow the driving etiquette that advises one to "stay right except to pass."

In many places this is the law, rather than just ettequite. :)

Of course, that doesn't mean people actually stay right unless they're passing.

In practice this cannot work. "Except to pass" allows for any nonzero differential speed. Someone will be doing 55MPH in the rightmost lane and someone will pass them at 55.1MPH, and someone will pass them in the left lane at 55.2MPH.

This is fine as long as each driver migrates back to the right as soon as feasible.

It's evolved sufficiently here in California that I believe Californian drivers now prefer to pass on the right rather than the left, given a choice.