SEATTLE — Now in its second week, the work to connect the new Highway 99 tunnel under Seattle to the rest of its namesake road continues to move quickly.

Contractor Scarsella Bros. was busy Monday pouring the final surface on the north embankment on the long northbound off-ramp into the city's stadium district at the south portal. Ironworkers were busy finishing the rebar work on the south embankment ready for the first of two layers of concrete there. 

A little over a week ago those embankments were wide open sections in the ramp where the southbound and northbound detours cut through up to the old Alaskan Way Viaduct.  

The viaduct closed to traffic the night of January 11. The tunnel is still on track to open February 4

RELATED: Survive the Seattle viaduct closure: What to know for your commute

Elsewhere, the road surface appears finished in and out of the north end of the project. 

A number of signs along the northern section of Highway 99 known as Aurora Avenue are now installed, directing people to the new left lane connection to Denny Way and the Seattle Center. 

Other signs warn drivers there are tolls ahead on the tunnel, although nobody will be charged for them until sometime this summer.  A date for toll collections to start has not yet been identified.

RELATED: Tunnel toll rates will range from $1 to $2.25

The contractor has benefited from incredibly good stretches of weather for January. Rain has not been a factor as the Washington State Department of Transportation says work can proceed in rainy conditions. Weather would becoming an issue if freezing temperatures hung around for more than a few hours, and could disrupt the schedule if winter weather were to drag on more than a week, according to David Sowers, the state's deputy project administrator. 

WATCH: Timelapse of construction work at south portal

It can take a week or more for concrete to cure to full strength to hold trucks and other heavy vehicles like buses. 

The off-ramp that ties into a new section of Dearborn Street is not expected to be finished until a week after the mainline and other ramps open. 

The project has attracted huge public interest, with more than 70,000 having signed up to say goodbye to the viaduct and hello to the tunnel during the grand opening weekend of February 2-3. WSDOT spokeswoman Laura Newborn says 20,000 have signed up for the 8K run, and 12,000 slots for the bike ride are sold out.

Join KING 5's Seattle Tunnel Traffic Facebook group to stay up-to-date on the latest Seattle tunnel and viaduct news and get tips to battle traffic during the three-week viaduct closure in January.