"With the bulk of journeys being made on SH1, we expect to see ongoing improvements to safety, access and journeys for those communities."
Owen said people should be aware the road would likely be very busy over the weekend as people took the opportunity to drive on it.
Waka Kotahi data showed about 85 per cent of all southbound morning journeys between 7am and 9am were made on Transmission Gully.
The remaining 15 per cent continued to use the existing coastal route.
The vast majority, 80 per cent, of heavy vehicles chose to use Transmission Gully.
While Waka Kotahi has pitched the first day of the new road as "running smoothly", there have been some teething issues.
Motorists were left with chipped and cracked windscreens yesterday because of the fresh chipseal.
Speed limits were temporarily reduced to 70km/h in some sections and the road was swept overnight.
Waka Kotahi also reported some issues at Linden in both northbound and southbound directions.
Drivers have been seen cutting across three lanes of traffic and making last-second changes to get onto Transmission Gully.
The merge at Linden is a new layout that might not be familiar to Wellington commuters and was designed to help avoid any possible safety or congestion issues, Owen said.
He said people should merge and change lanes safely, as well as taking some time to become familiar with the network.
"We would especially like to encourage people driving in the left lane coming from SH1 Transmission Gully to wait until they're near the end of the lane before merging. This gives everyone more time to notice other vehicles and prepare for a safe and efficient merge.
"Please, be patient, be courteous, and be safe.
