SEATTLE — Take a drive through the new State Route 99 tunnel under downtown Seattle with the Washington State Department of Transportation.

We began at the north portal in South Lake Union and drove southbound towards SODO.

WATCH: GoPro tour inside Seattle tunnel

From the north, drivers can get into the tunnel from an on-ramp on Sixth Avenue North between Mercer and Harrison Streets. Southbound drivers can get off SR 99 using left-side off-ramp to South Royal Brougham Way and Frontage Road.

RELATED: How to navigate the SR 99 tunnel from the north

From the south, drivers can get in the tunnel using the on-ramp at South Royal Brougham Way and Frontage Road. They can exit SR 99 after the tunnel onto Mercer Street.

RELATED: How to navigate the SR 99 tunnel from the south

The tunnel is expected to open to traffic Monday in time for the morning commute, according to David Sowers, deputy program administrator for the viaduct replacement program.

Before it opens, the public will get a chance to walk the 1.7-mile-long tunnel this weekend during a grand opening celebration. Tickets are all sold out to walk the viaduct, but there are some left for tunnel access.