Dr. Gridlock chatted with readers on Monday afternoon, discussing traffic on the Dulles Toll Road, lighting at Metro stations and more. For more, check out the complete transcript.

If you have any questions, comments or concerns for Dr. Gridlock, he’ll be chatting with readers next Monday at noon. Head here to submit questions in advance.

Mark Berman covers national news for The Washington Post and anchors Post Nation, a destination for breaking news and stories from around the country.