During my online chat Monday, travelers said they were concerned about the new work along the northbound George Washington Parkway, which has begun to back up traffic. It’s the next phase of a National Park Service project to shore up the rocks around Spout Run.

The project, managed by the Eastern Federal Lands Highway Division of the Federal Highway Administration is scheduled to continue well into December. Workers will be drilling into the rocks and installing bolts to stabilize an area north and south of the Spout Run Parkway, a short distance north of the Key Bridge in Rosslyn.

The left lane will be closed at all times. The others will be open for rush hours. But between 10 a.m. and 2:30 p.m. weekdays, only one northbound travel lane will be available. No night work has been scheduled, but drivers may find that the northbound lanes shrink down to one on weekends.

While it’s best not to have rocks falling on drivers, the work sets up a long-term traffic problem. One commenter said during the chat that the left-lane closing backs up evening rush hour traffic before Memorial Bridge and jams the Roosevelt Bridge.

In fact, I think the effects may be seen through Georgetown, along the E Street Expressway and on Constitution Avenue NW as well.

The description of the stabilization project may sound familiar to parkway drivers. In the late fall and winter, the park service launched a temporary stabilization effort to shore up the area while planning the current program, intended to ensure long-term safety.

The park service and the highway division suggest a few alternative routes to avoid the worst congestion. One is to use westbound Route 50. Another is to get off the GW Parkway at Spout Run Parkway (the exit is still open) and take that to Route 29, then take Interstate 66 west to the Capital Beltway.

A variation on that: From Route 29, turn right onto Military Road, then turn right onto North Glebe Road heading toward the Chain Bridge. Before the bridge, turn left onto Chain Bridge Road, then use the ramp back onto the George Washington Parkway before reaching the Beltway. See a map of that route.

Judging by what’s happened the past few days, drivers will have endured a lot of congestion just getting to the Spout Run Parkway exit. So avoiding the GW Parkway just north of Key Bridge — if possible — would be a better option.