Some drivers will do anything to get out of heavy traffic, including a fast run along an exit lane. (Juana Arias – The Washington Post)

To auto racers, “dive-bombing” refers to the act of accelerating, cutting to the inside of a corner and then braking hard to avoid hitting a barrier while passing a very nearby competitor, who may or may not wind up colliding with the passing car. Some racers say it’s a slick move, others a stupid one.

Commuters use the term more broadly. They’re describing another car pulling out of heavy traffic, speeding up, and then cutting back into the lane. They use it to spark the same sort of ethical debate as in racing — only we’re not supposed to be racing. There’s no prize for beating the competition to work.

The commuting scenarios include these: Pulling out of heavy traffic onto a shoulder, onto an exit ramp, onto a merge lane, onto an HOV lane, onto a turn lane or into a highway rest area. They also include rushing past signs warning that a lane ends in road work.

The commuter critics — and most commuters I hear from do criticize this behavior — say it’s unsafe and unfair. Unsafe because it often ends in heavy braking and a sharp move back into the travel lane. Unfair because, well, we’re all in this together and everyone should share the pain.

Defenders, at least those who are willing to come forward, say the best thing for all concerned is that we should spread out and use the available asphalt.

The safety argument is rock solid. Some of these folks are aggressive drivers who will do anything to gain a few car lengths. But in some circumstances, the ethical argument can get a little spongy.

Merging for a work zone is a good example: Many traffic engineers argue for the zipper merge, in which drivers use the full capacity of the through lane and the disappearing lane right up to the end, where they take turns into the through lane. Use all the pavement you’ve got, say these engineers. And to you drivers who remained in the through lane, these engineers say: It works better for everyone if you open up space for the other drivers to merge, even if you think they gained an unfair advantage by coming up in the more lightly traveled lane.

More erosion on the engineering side of the argument: Highway departments are opening up shoulders at peak periods, and they’re picking spots where they can extend merge lanes to the point where they become travel lanes. They don’t do this to encourage aggressive driving, but rather to allow drivers to take advantage of all the pavement they can provide without expanding the footprint of the highway.

A few years ago, Maryland opened shoulders on Route 29 to bus traffic at peak periods. Virginia just did the same on Interstate 66 inside the Capital Beltway. Virginia commuters have plenty of experience using the shoulders on I-66 outside the Beltway when the green arrows above the shoulders are illuminated. They’ll see a similar open shoulder in the Beltway’s inner loop this spring.

Through traffic takes advantage of the new collector-distributor lanes on I-95 near the Intercounty Connector in Maryland. Virginia is extending merge lanes on I-66 inside the Beltway in a series of three spot improvements.

One thing all such projects have in common is that the additional space ends all too quickly and the drivers must merge back into the regular travel lanes.

Here are some examples of driver sentiment drawn from Monday’s online chat.

Q: Exit Lane Dive-bombers
I think one of the most frustrating parts of my commute on I-66 East every morning are the folks that use the 123 exit lane to skip around traffic (dive-bombers). This is, of course, illegal. I would roughly estimate that at least 50 percent of cars that get off at 123 are dive-bombers (they are easy to spot). They do probably skip ahead a few car lengths, but they make traffic backups worse than they need to be.

Q: “Dive-bomber”
Contrary to what the [original poster] thinks, “dive-bombers,” more commonly referred to as ramp runners are completely legal, and many traffic engineers actually feel that they are good since they are taking advantage of every square inch of pavement available for traffic. The only consideration would be that some ramp runners go a bit too fast down the open ramp before running up on returning traffic, potentially causing an unsafe situation.

Q: Dive-bombers
I often see an officer at the end of the exit ramp on the inner loop for the exit before 355. This officer often gives tickets for these dive-bombers. Do it at your own risk but it is caught very often in this spot.

[DG: In this area of the Beltway, drivers will see a sign warning that the lane is for exit only onto southbound Route 355. But many drivers will wait till the very last moment, then brake hard and merge left across double white lines.]

I-370 onto I-270 – dive-bomber
Speaking of ramp runners, there is a regular issue where 370W exits onto 270S every morning. Traffic backs up in the lane that becomes an exit only lane, the far left lane. Traffic in the other two lanes is typically traveling at least 50 mph. Every day, someone decides they don’t want to wait in the long back up line and tries to slip in at the front of the line but since they are not able to do so easily they come to a complete stop or suddenly slow to 5 mph in a lane that is a through lane and traffic is traveling at a high rate of speed. Often there are several of these people who are more important than the rest of us.

I see the most flagrant use of the dive-bombing/merging at the confluence of the I-270 Spur and I-495. It’s terrible and the backup sometimes begins at the American Legion Bridge. There’s no other recourse to getting up 270 in a timely manner (as if such a thing were possible) but to move as far up to the split as possible and merge at the last minute. To queue up in the left lanes and slowly grind your way up the spur adds dozens of minutes onto the commute and only increases the misery.

Dive-bombing is perfectly legal as long as you do not cross any double solid white lines. Crossing the double white on the inner loop approaching 355 is illegal. But choosing a different route to get to your destination, i.e. “riding the ramps,” is perfectly legal in the absence of a sign prohibiting the move. There are quite a few locations in the D.C. area where you can use this to your advantage, but you really have to know the roads to know where the lanes exist, and where they jam up really badly so that they are worse than just staying the course. One such example is I-66 at Vienna Metro.