Joseph Stromberg explains why motorists shouldn't drive slowly in the left lane—a habit of many drivers that is all too familiar and frustrating to even the most safety-conscious drivers.
As Stromberg explains there's a legal case for staying to the right whenever possible: "every state has some sort of law that discourages people from traveling in the left lane on multi-lane roads and highways. It's not that you're never allowed in the left lane, just that you should only use it when necessary, for passing, then get back over."
Although that seems like an unlikely reason to be pulled over and ticketed, that might be changing: "police in several states — including Washington, Texas, and Ohio — have increasingly been issuing tickets to people they spot traveling slowly in the left."
For anyone who advocates for slower speeds on city streets and arterials, it might make rational sense that driving in the fast lane at the legal speed limit can slow down potential speeders, thus making roads safer, but the evidence does not back up that line of thinking. (It's doubtful, anyway, that many people guilty of clogging the left lane are so deliberate.) Here's how Stromberg sums the research findings on the matter, with more details in the article: "Unfortunately, there isn't much research on the effect of impeding people from passing in the left lane specifically. But there is evidence that slowing down and changing lanes is more dangerous than speeding."