We’ve all seen it. Construction signs ahead warning of two lanes of highway traffic merging into one.
Most motorists are following what they consider to be proper roadway etiquette: Move to the open lane as soon as possible.
But then, out of nowhere, there’s that driver who speeds down the now-empty lane and cuts to the front of the line.
In traffic lingo, they’re known as late mergers. The rest of us call them something else less flattering.
As it turns out, late mergers aren’t the scourge of society.
In fact, a study from the Minnesota Department of Transportation showed that when traffic is congested, late merging shortens the length of backups, is safer because both lanes of traffic are moving near the same speed and, most surprisingly, reduces road rage.
Road rage was what prompted the state to do the study.
“We were seeing a problem in road rage in work zones,” said Jon Jackels, an intelligence transportation system program engineer for the Minnesota Department of Transportation. “It was a fairness issue. People felt like it wasn’t fair.”
So, Minnesota started posting signs that encouraged drivers to use both lanes when traffic was congested and to take turns when merging.
“We told people it was fair to be in that lane, you were not a cheater, you were allowed to be in the other lane,” Jackels said. “For some, it was a hard pill for them to swallow.”
In his national bestseller “Traffic: Why We Drive the Way We Do (and What It Says About Us),” Tom Vanderbilt noted that when people merged late, the full capacity of the road was used. He also argued it is a fairer system because everyone merges at a single point instead of having a thousand feet to jump lanes or jockey for position.
“Merging late, that purported symbol of individual greed, actually makes things better for everyone,” Vanderbilt writes.
Jackals, who worked on the study, says the late merge approach isn’t the final answer. In rural areas where traffic doesn’t have to slow down, Minnesota encourages drivers to merge early.
While late merging does keep other intersections from being blocked, traffic doesn’t move any faster through a work zone and it can be difficult on highways with more than two lanes.
“Some engineers say what you guys are doing is nuts,” Jackels said.
The Kansas Turnpike Authority has a similar approach to Minnesota concerning how traffic should merge in the work zone east of Lawrence on Interstate 70.
On days when traffic flows smoothly, project engineer Rex Fleming asks that when drivers see the merge ahead signs, they move into the right lane at the speed they are going.
“That is like 95 percent of the time,” Fleming said.
But sometimes the KTA encourages drivers to use both lanes.
“On Fridays or when there is an accident and we get congestion, what happens is traffic backs up and what we don’t want to happen is to have that congestion get back past our work area,” he said.
The goal is to not block the west Lawrence exit, which would cause further congestion.
When congestion is ahead, Fleming urges drivers to stay in the lane they are in until it is time to merge.
And remember common courtesy, he said.
“When you get to a point where you have to merge together, do it nicely,” he said.