Commuters who drive through Tysons Corner are about to see some big changes in the work zone for the high-occupancy toll lanes.

If work scheduled for this weekend proceeds on schedule, then Monday morning commuters will find the four lanes of the Capital Beltway’s inner loop (Interstate 495 North) have shifted to the right onto a new bridge over Chain Bridge Road.

Perhaps most significant to commuters, this shift will allow the reopening of the ramp that leads from the right side of northbound Chain Bridge Road (Route 123) onto the inner loop. That will eliminate the left turn lanes and the traffic light that served as a temporary entrance to the inner loop.

All this work is linked to the creation of extra lanes on the Beltway that by the end of 2012 will allow the HOT lanes to enter service. Drivers who want to use the HOT lanes will have three interchanges in Tysons: Route 7, Westpark Drive and Jones Branch Road. The latter two will be new interchanges. (There won’t be a HOT lanes interchange at Route 123.)

But more immediately, many drivers will welcome the restoration of the Route 123 ramp and the restoration of the left lanes on Route 123 in both directions where they pass under the Beltway. The traffic light that was necessary to accommodate the left turns onto the inner loop will be eliminated.

Weekend work

Crews will be very active in the work zone this weekend as they prepare for the changes. This work is scheduled for Friday and Saturday nights.

From 9:30 p.m. Friday till 8:30 a.m. Saturday, the three right lanes on the inner loop from Route 7 to the Dulles Toll Road will be closed to prepare for the traffic shift. Ramps from the inner loop, Route 7 and Route 123 also will be closed. Detours will be marked.

From 9:30 p.m. Saturday to 9 a.m. Sunday, workers will close two left lanes on Route 123 to restore the left lanes, remove the traffic signals and reopen the ramp from Route 123 North to the inner loop. Ramps from the inner loop and Route 123 will be closed and detours marked.

This prep work originally was scheduled for last weekend, and was delayed by bad weather. But this segment of the Beltway expansion — the part that closed the ramp and made the left turn lanes necessary — originally was scheduled to continue into 2012 and is wrapping up well ahead of time.