(Updated at 9:15 a.m.) Westbound I-66 has been backed up for much of the latter half of the morning rush hour due to an accident near the Dulles Toll Road.

Traffic is very slow on the entire length of westbound I-66, from Rosslyn to the Toll Road. The backups are so bad that there are reports that ancillary backups have formed on some main local roads that connect with I-66 on-ramps, like Sycamore Street, Washington Boulevard and Glebe Road. Route 110 is also said to be jammed as a result of the I-66 traffic.

Via Twitter, several I-66 commuters have said that the slow traffic has added 30 or more minutes to their westbound commute.

WTOP is reporting that only one lane of I-66 is squeezing by the accident at the Toll Road.