As Washington officials enacted restrictions to slow the spread of the novel coronavirus this spring, traffic on highways and interstates began to decline.

Fewer people traveled as more limitations were placed on schools and large gatherings. After March 25, when Gov. Jay Inslee ordered residents to stay home, except for essential travel, traffic nose-dived. Now, vehicle travel is starting to creep up as some businesses and activities start to reopen.

Traffic Lab is a Seattle Times project that digs into the region’s thorny transportation issues, spotlights promising approaches to easing gridlock, and helps readers find the best ways to get around. It is funded with the help of community sponsors Madrona Venture Group and PEMCO Mutual Insurance Company. Seattle Times editors and reporters operate independently of our funders and maintain editorial control over Traffic Lab content.

The maps below compare traffic patterns on Monday, Jan. 13, to those on Monday April 27. Overall, the maps show that while travel on major highways and freeways declined, traffic on neighborhood streets increased.

These maps are based on GPS mobile device data collected anonymously from the company Mapbox, which provides a mapping platform used by over 45,000 apps including Facebook, Snapchat, and The Weather Channel.

They show that fewer people traveled on Interstate 5 in April than in January, before the outbreak. The Washington State Department of Transportation (WSDOT) says I-5 traffic in King County dropped nearly 40% during that same time frame.

Mapbox software may not pick up users’ locations when they travel underground, so traffic in the Highway 99 tunnel was not included in these maps. However, WSDOT tolling data shows an 81% drop in traffic there.

While Mapbox data did not show a significant change in Highway 520 traffic after the stay-home order, WSDOT recorded a nearly 74% drop. The agency reported a 58% decrease in traffic on Interstate 90.

Neighborhood streets, though, became busier. On April 27, Mapbox recorded traffic on about twice as many neighborhood and residential streets as was recorded on Jan. 13.