The Virginia government has set 2017 as its target for creating high-occupancy toll lanes on Interstate 66 inside the Capital Beltway, but that schedule is quite ambitious.

One key point is the planned adjustment of the rules for carpoolers, who can travel for free in HOT lanes as long as they meet the minimum standards. Right now, the minimum standard is two people per car. The I-66 proposal that Virginia submitted to the region’s Transportation Planning Board last week noted that Virginia has been planning to change that to three people per car by 2020, but could advance the change to 2017 to coincide with the HOT lanes conversion.

Virginia, Maryland and the District all submit big transportation plans like this for eventual inclusion in the region’s Constrained Long Range Plan. The plan is financially constrained, meaning that the sponsors have figured out how they would pay for the projects. Projects may come and go from the CLRP list, but because of there’s a realistic chance of paying for each project, it’s much more than a “Wouldn’t it be nice?” list of dreams.

So Virginia’s HOT lanes proposal for I-66 inside the Beltway includes this statement about the anticipated change in carpool occupancy.

The region’s current Constrained Long Range Plan calls for all HOV lanes in Northern Virginia to be HOV3+ by 2020. Allowing HOV3 vehicles to ride free is consistent with this policy change, and will also match the occupancy requirement on I-495 and I-95 Express Lanes. The project provides a seamless network of express lanes by connecting to adjacent express facilities.

But moving up the timetable for HOV3 inside the Beltway would put the system out of sync with the HOV2 rules for the I-66 carpool lanes outside the Beltway. The morning’s HOV2 commuters would need to make a choice once they reach the Beltway: Continue on I-66 and pay the rush hour toll, or get onto the Beltway and pick another connecting route for the rest of the trip to work.

The I-66/Beltway interchange doesn’t need much help to get jammed up at rush hours, which is one reason that the timing of the HOV rule change will get a lot of attention among transportation officials, commuters and community groups.

Renee Hamilton, deputy administrator for the Virginia Department of Transportation’s Northern Virginia District, said last week that many details about the HOT lanes program — both inside and outside the Beltway — must still be worked out. The HOV timetable is high on that list.

At a public meeting Thursday, she said the department was “just embarking” on the inside-the-Beltway project.

Many aspects of the HOT lanes project for outside the Beltway are farther along in the planning process. In fact, it was that project — not the inside-the-Beltway one — that was the subject of the public meeting. Still, the outside-the-Beltway project would involve much more construction and has its own set of unresolved issues, including the design of the highway and the new connections with the HOT lanes.

I’m planning several more blog postings this week on the plans for I-66. Questions and comments are welcome. Also, there are two more public meetings this week about the outside the Beltway plan. Each is scheduled for 6 to 8:30 p.m. These are the days and locations.

Tuesday. Oakton High School cafeteria, 2900 Sutton Rd., Vienna.

Thursday. VDOT regional headquarters, 4975 Alliance Dr., Fairfax.