Update at 10:40 a.m. — The accident has been cleared and traffic is moving smoothly.
Four people have been injured, two seriously, in a wreck in the northbound HOV lanes of the 14th Street Bridge.
Nearly a dozen police, fire and medic units from Arlington and the District have responded to the accident scene. Northbound HOV traffic on I-395 is backed up to Washington Boulevard.
Several vehicles were involved in the collision.