It's something learned in kindergarten:
Get in line. Everybody takes turns.
Yet some motorists fail to grasp this courtesy.
They annoy other drivers by waiting until the last second before merging with traffic entering a construction zone where a lane is closed.
Then they dart or bull their way into the single-file traffic without so much as a turn signal or - even after being allowed in - a thank-you wave.
A tactic some truck drivers have adopted to combat this behavior can be equally irritating.
They run side-by-side in the lanes approaching the work zone, forming a rolling roadblock intended to force those behind them to fall in line sooner than they otherwise might be inclined to.
"It's a take-your-place-in-line thing," Dale Stein, a truck driver from Sullivan, Wis., said during a recent fuel stop near the Ohio Turnpike in Lake Township.
"A car driver has no more right than a truck to get ahead, and this discourages line hopping," he said.
Mr. Stein said he could not recall whether he himself had ever teamed up with another trucker to run side-by-side approaching a construction zone, but called it "a good idea."
It's also illegal, said authorities in Ohio, Michigan, and Pennsylvania.
"Under Ohio's slow-speed law, they can be charged with impeding traffic," said Lt. Rick Zwayer, a spokesman for the Ohio State Highway Patrol.
"Trucks are not allowed to block traffic," said Ann Readett, a spokesman for the Michigan Office of Highway Safety Planning.
In Pennsylvania, where various repair and reconstruction projects have created a series of construction zones along mountainous, truck-laden I-80, authorities have gone so far as to post signs at certain work zones stating "Use Both Lanes to Merge Point," followed by "Merge Here, Take Your Turn."
Rich Kirkpatrick, a spokesman for the Pennsylvania Department of Transportation, said such signs have been used in that state for five years.
It is up to PennDOT's local districts to decide which work zones should get the signs, he said, but for the most part they are deployed "in areas where heavy volume is expected, and we want to take advantage of the road's lane capacity" right up to the beginning of the construction traffic backup.
"The point is not to merge into the only lane too soon, which only worsens the backup," Mr. Kirkpatrick said.
But whether or not such signs are posted, it is not a driver's role to dictate to others where they should merge, said Maj. John Duignan, director of the Pennsylvania State Police patrol bureau.
"I anticipate that the truckers believe they're enhancing safety by doing this, but I don't know that it's the job of a professional truck driver to take traffic control into their own hands," Major Duignan said.
Janet Foran, a Michigan Department of Transportation spokesman, said state officials there have begun using "Do Not Pass" signs, posted ahead of the actual lane closing, to discourage last-second lane dodgers.
At one zone near Kalamazoo, the no-passing sign has flashing lights that are activated when traffic volume reaches a certain level.
The signs' purpose is to tell motorists that they should not pass any more vehicles before getting in line, Ms. Foran said. Those convicted of violations are subject to fines and court costs of $100 or more, plus three points assessed to their licenses, she said.
Brian Cunningham, a spokesman for the Ohio Department of Transportation, said the agency experimented during the mid-1990s with signs that provided merging instructions, but determined they had no measurable effect on driver behavior or work-zone congestion. Since then, he said, the department's major effort to reduce traffic delays has been to schedule construction work so that when possible, at least two lanes are kept open on major roads during peak travel periods.
Edwin Nagle III, president of a Lake Township trucking company, said ODOT's two-lane policy has been "a big success."
"It really is a shame that other states haven't adopted that philosophy," he said.
But Mr. Nagle said he understands why his drivers may be inclined to join rolling roadblocks.
"Cars keep rushing up to the merge point. The flow of traffic into the reduced-lane area moves much faster when they can't do that," he said. "Everybody in the world is in a hurry to go nowhere fast."
Vicky Kimmel, a trucker from Clarion, Pa., said she has seen truckers get ticketed for obstructing traffic and won't do it herself, but doesn't mind when she benefits from other drivers teaming up.
"We have to give a lot of following distance, and when cars cut in there, then we don't have that stopping distance any more," she said. "Patience is the No. 1 thing. People get frustrated and do a lot of foolish things."
"The trucks are concerned about vehicles occupying their stop room," said Sgt. Jeffrey Hopkins, a spokesman for the Pennsylvania State Police.
But when truckers start taking traffic control into their own hands, he said, "it creates a situation of anarchy."
Police officials said motorists observed seen making unsafe lane changes will get tickets, and so will trucks that throw their weight around.
"They're not in charge of controlling the traffic flow," Lieutenant Zwayer said.
"It may be well-intentioned, but it's against the law," he said.
Contact David Patch at: firstname.lastname@example.org or 419-724-6094.