During Tuesday’s discussion about September Shocks connected to construction and federal base realignments, 1995hoo pointed out an upcoming event on the Capital Beltway that is bound to confuse some drivers: The inner loop’s left lane exit to Interstate 66 West is scheduled to close permanently.

That’s a significant change, but just one of many drivers will see over the next year as the D.C. region’s biggest road project, construction of the Virginia high occupancy toll lanes, moves toward completion at the end of 2012.

For example, the left exit from eastbound I-66 to the Beltway also will disappear as the project advances. In each of these cases, drivers will use the existing exits on the right side of the highways.

The elimination of the left exits at the Beltway interchange is part of the complex reconstruction that will create four HOT lanes in the middle of the Beltway, plus the ramps and bridges needed to accommodate them.

According to the Virginia Department of Transportation schedule, Exit 49C from the inner loop to westbound I-66 will be closed late this month. All inner loop drivers heading to westbound I-66 will then use the right-side ramp, Exit 49A, which is being widened to accommodate the extra traffic.

As with most changes in traffic patterns, it will take drivers at least a few weeks to get used to the alteration, despite the use of highway signs as reminders. And 1995hoo worried about drivers who rely on their GPS navigation systems. When roads are reconfigured, it takes a while for the electronic maps to catch up.

I’ll remind you about the exit closing when it’s about to occur. Then watch for some additional traffic congestion at the I-66 interchange. Meanwhile, construction and lane closings continue all along the 14-mile work zone for the HOT lanes between the Springfield interchange and the Dulles Toll Road.