[Update: Facebook commenters pointed out that the behavior I’m advocating for is already legal per Washington Administrative Code 468-510-020, which lifts the “keep right” requirement for the 40-mile stretch of I-5 from Tukwila to Everett, and on I-90 between I-5 and I-405.]

Every June, the National Motorist Association uses its own Lane Courtesy Month to produce a rush of news stories about the scourge of “left lane camping,” or drivers who remain in the left lane despite another motorist wishing to pass. A representative paragraph from Vox:

That’s because even if you’re driving fast, there’s always someone going faster. If you promptly get back over after passing, that car will be able to pass you, allowing everyone on the road to get to their destinations as quickly as possible. If you don’t, it’ll inevitably lead to buildups of traffic and likely raise the chance of accidents.

That same reporter, in a conversation this year with NPR’s Robert Siegel:

When you’re traveling on the highway, the moment at which you’re most at risk of getting into a crash is when you’re changing lanes. And when you have people going slow in the left lane, as well as the right lane, then people who want to move faster kind of have to zigzag back and forth. They have to change lanes looking over both different shoulders, and it just increases the amount of possible accident scenarios that can happen.

Look at the two statements I bolded above, which to me seem inherently contradictory in urban settings. “There’s always someone going faster” assumes both the right of drivers to create differential speed conditions and your responsibility to yield to their desires. But the Solomon Curve shows one of the most dangerous driving behaviors is deviating from the median speed of traffic, whether slower or faster. So if you’re traveling near the speed limit in the left lane, you should have zero responsibility to move over and are in fact doing a favor for overall safety and flow. The notion of constant lane-switching to appease lead footed drivers is contradicted by the same writer’s second statement, that changing lanes is inherently one of the riskiest behavior. These two are irreconcilable.

On rural highways where there is arguably a legitimate expectation of free flowing traffic at high speeds, sure, keep right except to pass. But in urban areas, left-lane camping is not only justifiable, but can actually help traffic. Consider Seattle, where merging pressure creates daily gridlock already. We have a ton of left-side entrances, and a ton of left-side exits. I would posit that drivers making trips within urban areas should travel at prevailing speeds, should help to minimize differential speeds by other drivers, should minimize total lane changes as much as possible, and should remain in the lane nearest to their entry or exit point.

Consider a trip from Montlake to West Seattle. A driver merges onto SR 520 for a left exit onto I-5, which merges into the left lane of I-5. Most traffic will be merging right to access the central city, with the through lane being the left lane. Such a driver should stay left through Downtown, only merging right for the West Seattle Bridge ramp. Or consider a trip from Northgate to Bellevue. From Northgate Way, this driver should merge left immediately and camp there for the left-side SR 520 exit, rather than waiting until the last minute and blowing up traffic with 5 sudden lane changes.

Urban traffic is all about driving predictably and going with the flow, and the prime directive should be to avoid causing system disruptions either by speeding or by enabling speeding by retaining the dangerous cultural norm and always moving right. No one has a right to speed, speeding kills, and traffic flows better when the river is moving together at a reasonable pace. If left lane camping helps you do these things, you should have every right to do it.