Tauranga City Council received six complaints via social media.
Campbell said the feedback, and data collected during the trial, would now be considered before the agency went back to the community.
"The team will also be comparing the original traffic model to the reality," he said.
"We want to ensure the best overall, balanced solution for everyone travelling through the area, and will be making some more adjustments in the short term to prioritise safety, particularly around the SH29A-Hairini roundabout."
"The trial confirmed that, due to the number of vehicles on the roads at peak hours, we can improve travel times through one part of the intersection but not without affecting travel times in other parts of the network."
The new route resulted in morning traffic on Welcome Bay Rd backing up to original congestion levels, often beyond the suburb's shopping area and school.
Welcome Bay resident Stephen Parr said before the underpass was built, it typically took 45 to 60 minutes to get into town.
"When the underpass opened, there was a much faster exit from Welcome Bay until reaching the point of reaching the cars jammed up waiting to get across Turret Rd bridge.
"This trial has simply put us back to exactly the same level of delay as before the underpass opened."
Parr said the long-term roading plan had been a "fiasco".
"The very obvious blockage has been and continues to be the Turret Rd bridge. This is not a new problem."
Parr submitted to the council on the need for a wider bridge about 10 years ago, he said.
He has since made other submissions himself and as part of the Welcome Bay Transport Forum at recent hearings of the council's 10-year plan and Regional Land Transport Plan of the Bay of Plenty Regional Council.
Both councils have listened but were "nibbling at the problem".
Parr's comments were echoed widely on social media with some commuters labelling the trial "insane" and "appalling".
However, Papamoa commuter Andrew Johnson, who takes SH29A about 7.15am each day, said the trial had not made a big difference to his journey.
"On some days it has been better, but it's usually it takes about the same amount of time."
The council has been investigating what extra loading Hairini Bridge can take, but any further development involving the bridge remains unknown, for now.
Maungatapu Underpass
- The $45m project took three years to build
- It opened on June 22, 2018
- A new cycleway attached to the underpass is expected to be completed and opened next week
- Hairini St's access to Turret Rd has now been closed to regular traffic after becoming a bus lane
