Predictably, a search for “Washington traffic” yields an image of South Capitol Street.

Using GPS data from portable navigation products, TomTom—-the maker of many of these aforementioned products—-has been able to compile a list of the nation’s most traffic-clogged regions:

Rank CITY/REGION % of congested roadways
1 Seattle, WA 43%
2 Los Angeles, CA 38%
3 Chicago, IL 37%
4 Montgomery County, MD 37%
5 San Francisco, CA 35%
6 New York, NY 31%
7 Washington, DC 30%
8 San Jose, CA 29%
9 Alexandria, VA 28%
10 Oakland, CA (Alameda County) 28%

According to the press release, “Cities* were ranked as most to least congested according to how fast cars could travel on the street network. A city’s traffic was defined as congested if drivers could travel at only 70% or less of the posted speed limit, meaning on average an hour long commute included 20 minutes or more of significant delays.”

Image by Joe Schlabotnik, Flickr Creative Commons Attribution License