Drivers in Northern Virginia are used to seeing signs like these on I-95/395 stating rules and tolls for the HOT lanes. But the style about to be used for I-66 inside the Beltway will need to be different. (Linda Davidson/The Washington Post)

There were several unusual things about Monday’s groundbreaking ceremony for the high-occupancy toll lanes on Interstate 66.

First, there was no ground to break. At such events, the dignitaries are normally provided with shovels and a pile of dirt to dig into. At this one, the project’s go-ahead was marked by the illumination of an electronic message board proclaiming that the transformation of the interstate was about to begin.

The second noteworthy feature of the event was the presence of Arlington County Board Chair Libby Garvey (D). Those familiar with the decades of debate about the highway’s future might have expected Arlington leadership to shun a project that would do anything other than close the interstate.

The unusual photo ops matched the unusual nature of the I-66 HOT lanes program inside the Capital Beltway. Transportation planners say it is the first time in the nation that an entire highway will be remade in this manner.

Workers will install eight toll gantries and 125 signs over and around the interstate. That’s pretty much it for the construction phase.

Next year at this time, rush-hour drivers heading in the peak direction will need an E-ZPass tansponder to use the existing lanes of I-66. If they’re driving solo, they will pay a variable toll as they pass under the gantries. If they have at least one passenger, they can get an E-ZPass Flex transponder and use the carpool setting to qualify for a free ride.

This changes the nature of the highway without changing the basic design. There’s just not that much dirt for the workers to move to create this. It’s mostly about sensors, computers and message boards. So the groundless groundbreaking was appropriate.

That doesn’t mean the setup is simple.

“A lot of work went into those signs,” said Amanda Baxter, the Virginia Department of Transportation’s manager for the inside-the-Beltway portion of the I-66 makeover.

I believe it. Some travelers still have difficulty understanding how HOT lanes work. The new lanes on I-66 are even more complicated, so the signs directing drivers to them have to be different from those for the Beltway and the Interstate 95/395 HOT lanes.

Those are full-time HOT lanes, parallel to regular lanes that are open to all travelers. They are “express” lanes, in which traffic is always supposed to flow freely, in contrast with the often-sluggish progress in the regular lanes.

On I-66 inside the Beltway, there won’t be anything but HOT lanes during the peak hours in the peak direction. The new I-66 signs will have a green top and the word “TOLL” on a yellow field. When the peak period is over and the interstate changes back from HOT lanes to general-purpose lanes, the tolling information will go blank, or “NO TOLL” will be displayed.

Virginia Transportation Secretary Aubrey Layne said the setup would involve some lane and ramp closures in coming months but should “have a minimal impact on traffic.”

Complicated as the tolling system may be, it’s only part of the I-66 plan developed under the administration of Gov. Terry McAuliffe (D), who led the Monday ceremony.

McAuliffe made a compromise with the General Assembly that will widen four miles on the eastbound side of the interstate, but that comes later.

The part of the HOT lanes plan that’s most attractive to Arlingtonians is this: In advance of collecting the toll revenue, the state has allocated $10 million to finance 10 programs designed to help commuters leave their cars behind. Those programs, including enhanced carpooling facilities and commuter bus services, are scheduled to be active by the time the first toll payer goes under a gantry next summer.

They were picked by the Northern Virginia Transportation Commission based on their ability to meet the start date and their ability to move people. This is a key attraction to people such as Garvey: If the highway is going to be there, take the focus off moving more cars and put it on moving people.

At the ceremony held on a high school parking deck over I-66, McAuliffe described the complex set of programs as appropriate for attacking “the most congested road in the most congested region” in the nation.

Garvey wants him to get even more ambitious about it. She looks at that concrete deck and envisions creating decks of parkland along I-66, healing the gash created by the highway’s construction and reuniting neighborhoods it split apart.

Dr. Gridlock also appears Thursday in Local Living. Comments and questions are welcome and may be used in a column, along with the writer’s name and home community. Write Dr. Gridlock at The Washington Post, 1301 K St. NW, Washington, D.C. 20071, or ­email