There are 210,297 cars in the District of Columbia, which is more than in Wyoming, Vermont, and Alaska. While the land area of the District of Columbia is relatively small, the population is dense, so there are still a lot of people who own vehicles.
This is part of the reason that Washington, D.C. was ranked the third-worst city in the U.S. for traffic in 2019. A high volume of people in a confined area leads to congestion, particularly on weekends and during rush hour.
If you are planning a trip to D.C. and want to steer clear of the worst traffic within the city, avoid driving during the morning or evening rush of commuters. And use Google Maps or Waze to navigate the quickest route.