Cut-through traffic drops in Herndon, but capacity at key intersections still strained, study finds

Herndon Town Council members remain concerned by cut-through traffic and spillover from development in neighboring jurisdictions following a recently released traffic study.

At a town council meeting on Feb. 13, consultant Gorove Slade reported that cut-through traffic declined overall from 2019 to 2022, but several key intersections are operating beyond their capacity loads.

The study kicked off in 2022 after former council member Sean Regan asked the town to specifically study how the Dulles Toll Road affects cut-through traffic in Herndon. The scope of the study was later expanded to the entire town, Herndon Community Development Director Lisa Gilleran said.

Still, Councilmember Donielle Scherff cautioned that more study is needed to guide meaningful policy decisions.

“It toggles the pandemic, which is just this blip we can’t all explain…I hate to say it but it almost feels like we need to continue this for two more years,” she said, noting concerns about traffic along Spring Street, Van Buren Street and some parts of Herndon Parkway.

She argued the study offers a snapshot in time and should be extended to provide more comprehensive information, particularly as more people return to work and the new Silver Line stations are used more frequently.

Overall, the study found that cut-through traffic exiting and entering the town accounted for 34% of overall traffic in 2019, dipping to 26% in 2022. The most common origin was the intersection of Sterling Road and Old Ox Road, and the most common destinations were Elden Street and Sunset Hills Road.

Overall, cut-through traffic to and from the toll road only accounted for around 8% of all cut-through traffic in 2019 and 6% in 2022.

Gorove Slade also studied capacity between April 25 and May 2 at key intersections. The consultant found that four intersections are operating beyond their set levels of service or queue lengths:

• Dranesville Road and Herndon Parkway (in the a.m., p.m. and midday)
• Herndon Parkway and Spring Street (a.m. and p.m.)
• Van Buren Street and Herndon Parkway (p.m., midday)
• Sterling Road and Crestview Drive (p.m.)

Burgeoning development at Rivana at Innovation Station in Loudoun County — which is planned for 3,700 residential units and 3.5 million square feet of office space — is expected to increase traffic. Councilmember Keven LeBlanc said the development is concerning since it’s “right on our border.”

Gilleran noted that the town expects to see traffic “increase significantly” on the Old Ox Road portal into town as a result of development.

Town Manager Bill Ashton II noted that the town is well aware of the potential impacts of neighboring development on town roads.

Ashton II said state transportation officials are not analyzing the issue from a holistic persepective and instead taking an approach that foucses mostly on Loudoun County. The town is analyzing ways to improve congestion on Sterling Road, he said.

The challenge is that the town is unable to add lanes as easily as Loudoun County — where development is newer and less dense — due to the presence of established neighborhoods, Gilleran said.

“When you come to the town line, of course, we have established neighborhoods, and so, the prospect of adding lanes is not something that the town has ever considered to be a desirable solution,” she said.