While there are plenty more places with traffic issues in the DMV (D.C., Maryland, Virginia), the National Capital Region Transportation Planning Board has released its top ten bottleneck analysis in its report for the calendar year of 2021 (seen below). According to the report, bottlenecks are typically defined by a traffic queue upstream of the bottleneck, a beginning point for a queue, free flow traffic conditions downstream of the bottleneck that have returned to nominal or design conditions, a predictable recurring cause, and traffic volumes that exceed the capability of the confluence to process traffic.
The PDA Suite Bottleneck Tool offers several bottleneck ranking factors using tool-specific methodology: